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  24                  <h1>Coding Guidelines</h1>
  25                  <p>Ascraeus coding guidelines document</p>
  26                  <p style="display: none;"><a href="#start_here">Skip</a></p>
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  38  
  39  <p class="paragraph main-description">
  40      These are the phpBB Coding Guidelines for Ascraeus, all attempts should be made to follow them as closely as possible.
  41  </p>
  42  
  43  <h1>Coding Guidelines</h1>
  44  
  45      <div class="paragraph menu">
  46          <div class="inner">
  47  
  48          <div class="content">
  49  
  50  <ol>
  51      <li><a href="#defaults">Defaults</a>
  52      <ol style="list-style-type: lower-roman;">
  53          <li><a href="#editorsettings">Editor Settings</a></li>
  54          <li><a href="#fileheader">File Header</a></li>
  55          <li><a href="#locations">File Locations</a></li>
  56          <li><a href="#constants">Special Constants</a></li>
  57      </ol>
  58      </li>
  59      <li><a href="#code">Code Layout/Guidelines</a>
  60      <ol style="list-style-type: lower-roman;">
  61          <li><a href="#namingvars">Variable/Function/Class Naming</a></li>
  62          <li><a href="#codelayout">Code Layout</a></li>
  63          <li><a href="#sql">SQL/SQL Layout</a></li>
  64          <li><a href="#optimizing">Optimizations</a></li>
  65          <li><a href="#general">General Guidelines</a></li>
  66          <li><a href="#phprestrictions">Restrictions on the Use of PHP</a></li>
  67      </ol>
  68      </li>
  69      <li><a href="#styling">Styling</a>
  70      <ol style="list-style-type: lower-roman;">
  71          <li><a href="#cfgfiles">Style Config Files</a></li>
  72          <li><a href="#genstyling">General Styling Rules</a></li>
  73      </ol></li>
  74      <li><a href="#templating">Templating</a>
  75      <ol style="list-style-type: lower-roman;">
  76          <li><a href="#templates">General Templating</a></li>
  77          <li><a href="#stylestree">Styles Tree</a></li>
  78          <li><a href="#template-events">Template Events</a></li>
  79      </ol></li>
  80      <li><a href="#charsets">Character Sets and Encodings</a></li>
  81      <li><a href="#translation">Translation (<abbr title="Internationalisation">i18n</abbr>/<abbr title="Localisation">L10n</abbr>) Guidelines</a>
  82      <ol style="list-style-type: lower-roman;">
  83          <li><a href="#standardisation">Standardisation</a></li>
  84          <li><a href="#otherconsiderations">Other considerations</a></li>
  85          <li><a href="#placeholders">Working with placeholders</a></li>
  86          <li><a href="#usingplurals">Using plurals</a></li>
  87          <li><a href="#writingstyle">Writing Style</a></li>
  88      </ol>
  89      </li>
  90      <li><a href="#disclaimer">Copyright and disclaimer</a></li>
  91  </ol>
  92  
  93          </div>
  94  
  95          </div>
  96      </div>
  97  
  98      <hr />
  99  
 100  <a name="defaults"></a><h2>1. Defaults</h2>
 101  
 102      <div class="paragraph">
 103          <div class="inner">
 104  
 105          <div class="content">
 106  
 107  <a name="editorsettings"></a><h3>1.i. Editor Settings</h3>
 108  
 109      <h4>Tabs vs Spaces:</h4>
 110      <p>In order to make this as simple as possible, we will be using tabs, not spaces. We enforce 4 (four) spaces for one tab - therefore you need to set your tab width within your editor to 4 spaces. Make sure that when you <strong>save</strong> the file, it's saving tabs and not spaces. This way, we can each have the code be displayed the way we like it, without breaking the layout of the actual files.</p>
 111      <p>Tabs in front of lines are no problem, but having them within the text can be a problem if you do not set it to the amount of spaces every one of us uses. Here is a short example of how it should look like:</p>
 112  
 113      <div class="codebox"><pre>
 114  {TAB}$mode{TAB}{TAB}= $request->variable('mode', '');
 115  {TAB}$search_id{TAB}= $request->variable('search_id', '');</pre>
 116      </div>
 117  
 118      <p>If entered with tabs (replace the {TAB}) both equal signs need to be on the same column.</p>
 119  
 120      <h3>Linefeeds:</h3>
 121      <p>Ensure that your editor is saving files in the UNIX (LF) line ending format. This means that lines are terminated with a newline, not with Windows Line endings (CR/LF combo) as they are on Win32 or Classic Mac (CR) Line endings. Any decent editor should be able to do this, but it might not always be the default setting. Know your editor. If you want advice for an editor for your Operating System, just ask one of the developers. Some of them do their editing on Win32.</p>
 122  
 123      <a name="fileheader"></a><h3>1.ii. File Layout</h3>
 124  
 125      <h4>Standard header for new files:</h4>
 126      <p>This template of the header must be included at the start of all phpBB files: </p>
 127  
 128      <div class="codebox"><pre>
 129  /**
 130  *
 131  * This file is part of the phpBB Forum Software package.
 132  *
 133  * @copyright (c) phpBB Limited &lt;https://www.phpbb.com&gt;
 134  * @license GNU General Public License, version 2 (GPL-2.0)
 135  *
 136  * For full copyright and license information, please see
 137  * the docs/CREDITS.txt file.
 138  *
 139  */</pre>
 140      </div>
 141  
 142      <p>Please see the <a href="#locations">File Locations section</a> for the correct package name.</p>
 143  
 144      <h4>PHP closing tags</h4>
 145  
 146      <p>A file containg only PHP code should not end with the optional PHP closing tag <strong>?&gt;</strong> to avoid issues with whitespace following it.</p>
 147  
 148      <h4>Newline at end of file</h4>
 149  
 150      <p>All files should end in a newline so the last line does not appear as modified in diffs, when a line is appended to the file.</p>
 151  
 152      <h4>Files containing inline code:</h4>
 153  
 154      <p>For those files you have to put an empty comment directly after the header to prevent the documentor assigning the header to the first code element found.</p>
 155  
 156      <div class="codebox"><pre>
 157  /**
 158  * {HEADER}
 159  */
 160  
 161  /**
 162  */
 163  {CODE}</pre>
 164      </div>
 165  
 166      <h4>Files containing only functions:</h4>
 167  
 168      <p>Do not forget to comment the functions (especially the first function following the header). Each function should have at least a comment of what this function does. For more complex functions it is recommended to document the parameters too.</p>
 169  
 170      <h4>Files containing only classes:</h4>
 171  
 172      <p>Do not forget to comment the class. Classes need a separate @package definition, it is the same as the header package name. Apart from this special case the above statement for files containing only functions needs to be applied to classes and it's methods too.</p>
 173  
 174      <h4>Code following the header but only functions/classes file:</h4>
 175  
 176      <p>If this case is true, the best method to avoid documentation confusions is adding an ignore command, for example:</p>
 177  
 178      <div class="codebox"><pre>
 179  /**
 180  * {HEADER}
 181  */
 182  
 183  /**
 184  * @ignore
 185  */
 186  Small code snipped, mostly one or two defines or an if statement
 187  
 188  /**
 189  * {DOCUMENTATION}
 190  */
 191  class ...</pre>
 192      </div>
 193  
 194      <a name="locations"></a><h3>1.iii. File Locations</h3>
 195  
 196      <p>Functions used by more than one page should be placed in functions.php, functions specific to one page should be placed on that page (at the bottom) or within the relevant sections functions file. Some files in <code>/includes</code> are holding functions responsible for special sections, for example uploading files, displaying &quot;things&quot;, user related functions and so forth.</p>
 197  
 198      <p>The following packages are defined, and related new features/functions should be placed within the mentioned files/locations, as well as specifying the correct package name. The package names are bold within this list:</p>
 199  
 200      <ul>
 201          <li><strong>phpBB3</strong><br />Core files and all files not assigned to a separate package</li>
 202          <li><strong>acm</strong><br /><code>/phpbb/cache</code><br />Cache System</li>
 203          <li><strong>acp</strong><br /><code>/adm</code>, <code>/includes/acp</code>, <code>/includes/functions_admin.php</code><br />Administration Control Panel</li>
 204          <li><strong>dbal</strong><br /><code>/phpbb/db</code>, <code>/includes/db</code><br />Database Abstraction Layer.
 205              <ul>
 206                  <li><code>/phpbb/db/driver/</code><br />Database Abstraction Layer classes</li>
 207                  <li><code>/phpbb/db/migration/</code><br />Migrations are used for updating the database from one release to another</li>
 208              </ul>
 209          </li>
 210          <li><strong>diff</strong><br /><code>/includes/diff</code><br />Diff Engine</li>
 211          <li><strong>docs</strong><br /><code>/docs</code><br />phpBB Documentation</li>
 212          <li><strong>images</strong><br /><code>/images</code><br />All global images not connected to styles</li>
 213          <li><strong>install</strong><br /><code>/install</code><br />Installation System</li>
 214          <li><strong>language</strong><br /><code>/language</code><br />All language files</li>
 215          <li><strong>login</strong><br /><code>/phpbb/auth</code><br />Login Authentication Plugins</li>
 216          <li><strong>VC</strong><br /><code>/includes/captcha</code><br />CAPTCHA</li>
 217          <li><strong>mcp</strong><br /><code>mcp.php</code>, <code>/includes/mcp</code>, <code>report.php</code><br />Moderator Control Panel</li>
 218          <li><strong>ucp</strong><br /><code>ucp.php</code>, <code>/includes/ucp</code><br />User Control Panel</li>
 219          <li><strong>utf</strong><br /><code>/includes/utf</code><br />UTF8-related functions/classes</li>
 220          <li><strong>search</strong><br /><code>/phpbb/search</code>, <code>search.php</code><br />Search System</li>
 221          <li><strong>styles</strong><br /><code>/styles</code><br />phpBB Styles/Templates/Themes</li>
 222      </ul>
 223  
 224      <a name="constants"></a><h3>1.iv. Special Constants</h3>
 225  
 226      <p>There are some special constants application developers are able to utilize to bend some of phpBB's internal functionality to suit their needs.</p>
 227  
 228      <div class="codebox"><pre>
 229  PHPBB_MSG_HANDLER          (overwrite message handler)
 230  PHPBB_DB_NEW_LINK          (overwrite new_link parameter for sql_connect)
 231  PHPBB_ROOT_PATH            (overwrite $phpbb_root_path)
 232  PHPBB_ADMIN_PATH           (overwrite $phpbb_admin_path)
 233  PHPBB_USE_BOARD_URL_PATH   (use generate_board_url() for image paths instead of $phpbb_root_path)
 234  PHPBB_DISABLE_ACP_EDITOR   (disable ACP style editor for templates)
 235  PHPBB_DISABLE_CONFIG_CHECK (disable ACP config.php writeable check)
 236  
 237  PHPBB_ACM_MEMCACHE_PORT     (overwrite memcached port, default is 11211)
 238  PHPBB_ACM_MEMCACHE_COMPRESS (overwrite memcached compress setting, default is disabled)
 239  PHPBB_ACM_MEMCACHE_HOST     (overwrite memcached host name, default is localhost)
 240  
 241  PHPBB_ACM_REDIS_HOST        (overwrite redis host name, default is localhost)
 242  PHPBB_ACM_REDIS_PORT        (overwrite redis port, default is 6379)
 243  PHPBB_ACM_REDIS_PASSWORD    (overwrite redis password, default is empty)
 244  PHPBB_ACM_REDIS_DB          (overwrite redis default database)
 245  
 246  PHPBB_QA                   (Set board to QA-Mode, which means the updater also checks for RC-releases)
 247  </pre></div>
 248  
 249  <h4>PHPBB_USE_BOARD_URL_PATH</h4>
 250  
 251  <p>If the <code>PHPBB_USE_BOARD_URL_PATH</code> constant is set to true, phpBB uses generate_board_url() (this will return the boards url with the script path included) on all instances where web-accessible images are loaded. The exact locations are:</p>
 252  
 253  <ul>
 254      <li>/phpbb/user.php - \phpbb\user::img()</li>
 255      <li>/includes/functions_content.php - smiley_text()</li>
 256  </ul>
 257  
 258  <p>Path locations for the following template variables are affected by this too:</p>
 259  
 260  <ul>
 261      <li>{T_ASSETS_PATH} - assets (non-style specific, static resources)</li>
 262      <li>{T_THEME_PATH} - styles/xxx/theme</li>
 263      <li>{T_TEMPLATE_PATH} - styles/xxx/template</li>
 264      <li>{T_SUPER_TEMPLATE_PATH} - styles/xxx/template</li>
 265      <li>{T_IMAGES_PATH} - images/</li>
 266      <li>{T_SMILIES_PATH} - $config['smilies_path']/</li>
 267      <li>{T_AVATAR_PATH} - $config['avatar_path']/</li>
 268      <li>{T_AVATAR_GALLERY_PATH} - $config['avatar_gallery_path']/</li>
 269      <li>{T_ICONS_PATH} - $config['icons_path']/</li>
 270      <li>{T_RANKS_PATH} - $config['ranks_path']/</li>
 271      <li>{T_UPLOAD_PATH} - $config['upload_path']/</li>
 272      <li>{T_STYLESHEET_LINK} - styles/xxx/theme/stylesheet.css</li>
 273      <li>New template variable {BOARD_URL} for the board url + script path.</li>
 274  </ul>
 275  
 276          </div>
 277  
 278          <div class="back2top"><a href="#wrap" class="top">Back to Top</a></div>
 279  
 280          </div>
 281      </div>
 282  
 283      <hr />
 284  
 285  <a name="code"></a><h2>2. Code Layout/Guidelines</h2>
 286  
 287      <div class="paragraph">
 288          <div class="inner">
 289  
 290          <div class="content">
 291  
 292      <p>Please note that these guidelines apply to all php, html, javascript and css files.</p>
 293  
 294      <a name="namingvars"></a><h3>2.i. Variable/Function/Class Naming</h3>
 295  
 296      <p>We will not be using any form of hungarian notation in our naming conventions. Many of us believe that hungarian naming is one of the primary code obfuscation techniques currently in use.</p>
 297  
 298      <h4>Variable Names:</h4>
 299      <p>In PHP, variable names should be in all lowercase, with words separated by an underscore, example:</p>
 300  
 301      <div class="indent">
 302          <p><code>$current_user</code> is right, but <code>$currentuser</code> and <code> $currentUser</code> are not.</p>
 303      </div>
 304  
 305      <p>In JavaScript, variable names should use camel case:</p>
 306  
 307      <div class="indent">
 308          <p><code>currentUser</code> is right, but <code>currentuser</code> and <code>current_user</code> are not.</p>
 309      </div>
 310  
 311      <p>Names should be descriptive, but concise. We don't want huge sentences as our variable names, but typing an extra couple of characters is always better than wondering what exactly a certain variable is for. </p>
 312  
 313      <h4>Loop Indices:</h4>
 314      <p>The <em>only</em> situation where a one-character variable name is allowed is when it's the index for some looping construct. In this case, the index of the outer loop should always be $i. If there's a loop inside that loop, its index should be $j, followed by $k, and so on. If the loop is being indexed by some already-existing variable with a meaningful name, this guideline does not apply, example:</p>
 315  
 316      <div class="codebox"><pre>
 317  for ($i = 0; $i &lt; $outer_size; $i++)
 318  {
 319     for ($j = 0; $j &lt; $inner_size; $j++)
 320     {
 321        foo($i, $j);
 322     }
 323  }</pre>
 324      </div>
 325  
 326      <h4>Function Names:</h4>
 327      <p>Functions should also be named descriptively. We're not programming in C here, we don't want to write functions called things like "stristr()". Again, all lower-case names with words separated by a single underscore character in PHP, and camel caps in JavaScript. Function names should be prefixed with "phpbb_" and preferably have a verb in them somewhere. Good function names are <code>phpbb_print_login_status()</code>, <code>phpbb_get_user_data()</code>, etc. Constructor functions in JavaScript should begin with a capital letter.</p>
 328  
 329      <h4>Function Arguments:</h4>
 330      <p>Arguments are subject to the same guidelines as variable names. We don't want a bunch of functions like: <code>do_stuff($a, $b, $c)</code>. In most cases, we'd like to be able to tell how to use a function by just looking at its declaration. </p>
 331  
 332      <h4>Class Names:</h4>
 333  
 334      <p>Apart from following the rules for function names, all classes should meet the following conditions:</p>
 335      <ul>
 336          <li>Every class must be defined in a separate file.</li>
 337          <li>The classes have to be located in a subdirectory of <code>phpbb/</code>.</li>
 338          <li>Classnames must be namespaced with <code>\phpbb\</code> to avoid name clashes.</li>
 339          <li>Class names/namespaces have to reflect the location of the file they are defined in. The namespace must be the directory in which the file is located. So the directory names must not contain any underscores, but the filename may.</li>
 340          <li>Directories should typically be a singular noun (e.g. <code>dir</code> in the example below, not <code>dirs</code>.</li>
 341      </ul>
 342  
 343      <p>So given the following example directory structure you would result in the below listed lookups</p>
 344      <div class="codebox"><pre>
 345  phpbb/
 346    class_name.php
 347    dir/
 348      class_name.php
 349        subdir/
 350          class_name.php</pre>
 351      </div>
 352  
 353      <div class="codebox"><pre>
 354  \phpbb\class_name            - phpbb/class_name.php
 355  \phpbb\dir\class_name        - phpbb/dir/class_name.php
 356  \phpbb\dir\subdir\class_name - phpbb/dir/subdir/class_name.php</pre>
 357      </div>
 358  
 359  
 360      <h4>Summary:</h4>
 361      <p>The basic philosophy here is to not hurt code clarity for the sake of laziness. This has to be balanced by a little bit of common sense, though; <code>phpbb_print_login_status_for_a_given_user()</code> goes too far, for example -- that function would be better named <code>phpbb_print_user_login_status()</code>, or just <code>phpbb_print_login_status()</code>.</p>
 362  
 363      <h4>Special Namings: </h4>
 364      <p>For all emoticons use the term <code>smiley</code> in singular and <code>smilies</code> in plural. For emails we use the term <code>email</code> (without dash between “e” and “m”).</p>
 365  
 366      <a name="codelayout"></a><h3>2.ii. Code Layout</h3>
 367  
 368      <h4>Always include the braces:</h4>
 369      <p>This is another case of being too lazy to type 2 extra characters causing problems with code clarity. Even if the body of some construct is only one line long, do <em>not</em> drop the braces. Just don't, examples:</p>
 370  
 371      <p class="bad">// These are all wrong. </p>
 372  
 373      <div class="codebox"><pre>
 374  if (condition) do_stuff();
 375  
 376  if (condition)
 377      do_stuff();
 378  
 379  while (condition)
 380      do_stuff();
 381  
 382  for ($i = 0; $i &lt; size; $i++)
 383      do_stuff($i);</pre>
 384      </div>
 385  
 386      <p class="good">// These are all right. </p>
 387      <div class="codebox"><pre>
 388  if (condition)
 389  {
 390      do_stuff();
 391  }
 392  
 393  while (condition)
 394  {
 395      do_stuff();
 396  }
 397  
 398  for ($i = 0; $i &lt; size; $i++)
 399  {
 400      do_stuff();
 401  }</pre>
 402      </div>
 403  
 404      <h4>Where to put the braces:</h4>
 405      <p>In PHP code, braces always go on their own line. The closing brace should also always be at the same column as the corresponding opening brace, examples:</p>
 406  
 407      <div class="codebox"><pre>
 408  if (condition)
 409  {
 410      while (condition2)
 411      {
 412          ...
 413      }
 414  }
 415  else
 416  {
 417      ...
 418  }
 419  
 420  for ($i = 0; $i &lt; $size; $i++)
 421  {
 422      ...
 423  }
 424  
 425  while (condition)
 426  {
 427      ...
 428  }
 429  
 430  function do_stuff()
 431  {
 432      ...
 433  }</pre>
 434      </div>
 435  
 436      <p>In JavaScript code, braces always go on the same line:</p>
 437  
 438      <div class="codebox"><pre>
 439  if (condition) {
 440      while (condition2) {
 441          ...
 442      }
 443  } else {
 444      ...
 445  }
 446  
 447  for (var i = 0; i &lt; size; i++) {
 448      ...
 449  }
 450  
 451  while (condition) {
 452      ...
 453  }
 454  
 455  function do_stuff() {
 456      ...
 457  }</pre>
 458      </div>
 459  
 460      <h4>Use spaces between tokens:</h4>
 461      <p>This is another simple, easy step that helps keep code readable without much effort. Whenever you write an assignment, expression, etc.. Always leave <em>one</em> space between the tokens. Basically, write code as if it was English. Put spaces between variable names and operators. Don't put spaces just after an opening bracket or before a closing bracket. Don't put spaces just before a comma or a semicolon. This is best shown with a few examples, examples:</p>
 462  
 463      <p>// Each pair shows the wrong way followed by the right way. </p>
 464  
 465      <div class="codebox"><pre>
 466  $i=0;
 467  $i = 0;
 468  
 469  if($i&lt;7) ...
 470  if ($i &lt; 7) ...
 471  
 472  if ( ($i &lt; 7)&amp;&amp;($j &gt; 8) ) ...
 473  if ($i &lt; 7 &amp;&amp; $j &gt; 8) ...
 474  
 475  do_stuff( $i, 'foo', $b );
 476  do_stuff($i, 'foo', $b);
 477  
 478  for($i=0; $i&lt;$size; $i++) ...
 479  for ($i = 0; $i &lt; $size; $i++) ...
 480  
 481  $i=($j &lt; $size)?0:1;
 482  $i = ($j &lt; $size) ? 0 : 1;</pre>
 483      </div>
 484  
 485      <h4>Operator precedence:</h4>
 486      <p>Do you know the exact precedence of all the operators in PHP? Neither do I. Don't guess. Always make it obvious by using brackets to force the precedence of an equation so you know what it does. Remember to not over-use this, as it may harden the readability. Basically, do not enclose single expressions. Examples:</p>
 487  
 488      <p class="bad">// what's the result? who knows. </p>
 489      <div class="codebox">
 490          <pre>$bool = ($i &lt; 7 &amp;&amp; $j &gt; 8 || $k == 4);</pre>
 491      </div>
 492  
 493      <p class="bad">// now you can be certain what I'm doing here.</p>
 494      <div class="codebox">
 495          <pre>$bool = (($i &lt; 7) &amp;&amp; (($j &lt; 8) || ($k == 4)));</pre>
 496      </div>
 497  
 498      <p class="good">// But this one is even better, because it is easier on the eye but the intention is preserved</p>
 499      <div class="codebox">
 500          <pre>$bool = ($i &lt; 7 &amp;&amp; ($j &lt; 8 || $k == 4));</pre>
 501      </div>
 502  
 503      <h4>Quoting strings:</h4>
 504      <p>There are two different ways to quote strings in PHP - either with single quotes or with double quotes. The main difference is that the parser does variable interpolation in double-quoted strings, but not in single quoted strings. Because of this, you should <em>always</em> use single quotes <em>unless</em> you specifically need variable interpolation to be done on that string. This way, we can save the parser the trouble of parsing a bunch of strings where no interpolation needs to be done.</p>
 505      <p>Also, if you are using a string variable as part of a function call, you do not need to enclose that variable in quotes. Again, this will just make unnecessary work for the parser. Note, however, that nearly all of the escape sequences that exist for double-quoted strings will not work with single-quoted strings. Be careful, and feel free to break this guideline if it's making your code easier to read, examples:</p>
 506  
 507      <p class="bad">// wrong </p>
 508      <div class="codebox"><pre>
 509  $str = "This is a really long string with no variables for the parser to find.";
 510  
 511  do_stuff("$str");</pre>
 512      </div>
 513  
 514      <p class="good">// right</p>
 515      <div class="codebox"><pre>
 516  $str = 'This is a really long string with no variables for the parser to find.';
 517  
 518  do_stuff($str);</pre>
 519      </div>
 520  
 521      <p class="bad">// Sometimes single quotes are just not right</p>
 522      <div class="codebox"><pre>
 523  $post_url = $phpbb_root_path . 'posting.' . $phpEx . '?mode=' . $mode . '&amp;amp;start=' . $start;</pre>
 524      </div>
 525  
 526      <p class="good">// Double quotes are sometimes needed to not overcrowd the line with concatenations.</p>
 527      <div class="codebox"><pre>
 528  $post_url = "{$phpbb_root_path}posting.$phpEx?mode=$mode&amp;amp;start=$start";</pre>
 529      </div>
 530  
 531      <p>In SQL statements mixing single and double quotes is partly allowed (following the guidelines listed here about SQL formatting), else one should try to only use one method - mostly single quotes.</p>
 532  
 533      <h4>Commas after every array element:</h4>
 534      <p>If an array is defined with each element on its own line, you still have to modify the previous line to add a comma when appending a new element. PHP allows for trailing (useless) commas in array definitions. These should always be used so each element including the comma can be appended with a single line. In JavaScript, do not use the trailing comma, as it causes browsers to throw errors.</p>
 535  
 536      <p class="bad">// wrong</p>
 537      <div class="codebox"><pre>
 538  $foo = array(
 539      'bar' => 42,
 540      'boo' => 23
 541  );</pre>
 542      </div>
 543  
 544      <p class="good">// right </p>
 545      <div class="codebox"><pre>
 546  $foo = array(
 547      'bar' => 42,
 548      'boo' => 23,
 549  );</pre>
 550      </div>
 551  
 552  
 553      <h4>Associative array keys:</h4>
 554      <p>In PHP, it's legal to use a literal string as a key to an associative array without quoting that string. We don't want to do this -- the string should always be quoted to avoid confusion. Note that this is only when we're using a literal, not when we're using a variable, examples:</p>
 555  
 556      <p class="bad">// wrong</p>
 557      <div class="codebox">
 558          <pre>$foo = $assoc_array[blah];</pre>
 559      </div>
 560  
 561      <p class="good">// right </p>
 562      <div class="codebox">
 563          <pre>$foo = $assoc_array['blah'];</pre>
 564      </div>
 565  
 566      <p class="bad">// wrong</p>
 567      <div class="codebox">
 568          <pre>$foo = $assoc_array["$var"];</pre>
 569      </div>
 570  
 571      <p class="good">// right </p>
 572      <div class="codebox">
 573          <pre>$foo = $assoc_array[$var];</pre>
 574      </div>
 575  
 576      <h4>Comments:</h4>
 577      <p>Each complex function should be preceded by a comment that tells a programmer everything they need to know to use that function. The meaning of every parameter, the expected input, and the output are required as a minimal comment. The function's behaviour in error conditions (and what those error conditions are) should also be present - but mostly included within the comment about the output.<br /><br />Especially important to document are any assumptions the code makes, or preconditions for its proper operation. Any one of the developers should be able to look at any part of the application and figure out what's going on in a reasonable amount of time.<br /><br />Avoid using <code>/* */</code> comment blocks for one-line comments, <code>//</code> should be used for one/two-liners.</p>
 578  
 579      <h4>Magic numbers:</h4>
 580      <p>Don't use them. Use named constants for any literal value other than obvious special cases. Basically, it's ok to check if an array has 0 elements by using the literal 0. It's not ok to assign some special meaning to a number and then use it everywhere as a literal. This hurts readability AND maintainability. The constants <code>true</code> and <code>false</code> should be used in place of the literals 1 and 0 -- even though they have the same values (but not type!), it's more obvious what the actual logic is when you use the named constants. Typecast variables where it is needed, do not rely on the correct variable type (PHP is currently very loose on typecasting which can lead to security problems if a developer does not keep a very close eye on it).</p>
 581  
 582      <h4>Shortcut operators:</h4>
 583      <p>The only shortcut operators that cause readability problems are the shortcut increment <code>$i++</code> and decrement <code>$j--</code> operators. These operators should not be used as part of an expression. They can, however, be used on their own line. Using them in expressions is just not worth the headaches when debugging, examples:</p>
 584  
 585      <p class="bad">// wrong </p>
 586      <div class="codebox"><pre>
 587  $array[++$i] = $j;
 588  $array[$i++] = $k;</pre>
 589      </div>
 590  
 591      <p class="good">// right </p>
 592      <div class="codebox"><pre>
 593  $i++;
 594  $array[$i] = $j;
 595  
 596  $array[$i] = $k;
 597  $i++;</pre>
 598      </div>
 599  
 600      <h4>Inline conditionals:</h4>
 601      <p>Inline conditionals should only be used to do very simple things. Preferably, they will only be used to do assignments, and not for function calls or anything complex at all. They can be harmful to readability if used incorrectly, so don't fall in love with saving typing by using them, examples:</p>
 602  
 603      <p class="bad">// Bad place to use them</p>
 604      <div class="codebox"><pre>
 605  ($i &lt; $size &amp;&amp; $j &gt; $size) ? do_stuff($foo) : do_stuff($bar);</pre>
 606      </div>
 607  
 608      <p class="good">// OK place to use them </p>
 609      <div class="codebox"><pre>
 610  $min = ($i &lt; $j) ? $i : $j;</pre>
 611      </div>
 612  
 613      <h4>Don't use uninitialized variables.</h4>
 614      <p>For phpBB3, we intend to use a higher level of run-time error reporting. This will mean that the use of an uninitialized variable will be reported as a warning. These warnings can be avoided by using the built-in isset() function to check whether a variable has been set - but preferably the variable is always existing. For checking if an array has a key set this can come in handy though, examples:</p>
 615  
 616      <p class="bad">// Wrong </p>
 617      <div class="codebox">
 618          <pre>if ($forum) ...</pre>
 619      </div>
 620  
 621      <p class="good">// Right </p>
 622      <div class="codebox">
 623          <pre>if (isset($forum)) ...</pre></div>
 624  
 625      <p class="good">// Also possible</p>
 626      <div class="codebox">
 627          <pre>if (isset($forum) &amp;&amp; $forum == 5)</pre>
 628      </div>
 629  
 630      <p>The <code>empty()</code> function is useful if you want to check if a variable is not set or being empty (an empty string, 0 as an integer or string, NULL, false, an empty array or a variable declared, but without a value in a class). Therefore empty should be used in favor of <code>isset($array) &amp;&amp; sizeof($array) &gt; 0</code> - this can be written in a shorter way as <code>!empty($array)</code>.</p>
 631  
 632      <h4>Switch statements:</h4>
 633      <p>Switch/case code blocks can get a bit long sometimes. To have some level of notice and being in-line with the opening/closing brace requirement (where they are on the same line for better readability), this also applies to switch/case code blocks and the breaks. An example:</p>
 634  
 635      <p class="bad">// Wrong </p>
 636      <div class="codebox"><pre>
 637  switch ($mode)
 638  {
 639      case 'mode1':
 640          // I am doing something here
 641          break;
 642      case 'mode2':
 643          // I am doing something completely different here
 644          break;
 645  }</pre>
 646      </div>
 647  
 648      <p class="good">// Good </p>
 649      <div class="codebox"><pre>
 650  switch ($mode)
 651  {
 652      case 'mode1':
 653          // I am doing something here
 654      break;
 655  
 656      case 'mode2':
 657          // I am doing something completely different here
 658      break;
 659  
 660      default:
 661          // Always assume that a case was not caught
 662      break;
 663  }</pre>
 664      </div>
 665  
 666      <p class="good">// Also good, if you have more code between the case and the break </p>
 667      <div class="codebox"><pre>
 668  switch ($mode)
 669  {
 670      case 'mode1':
 671  
 672          // I am doing something here
 673  
 674      break;
 675  
 676      case 'mode2':
 677  
 678          // I am doing something completely different here
 679  
 680      break;
 681  
 682      default:
 683  
 684          // Always assume that a case was not caught
 685  
 686      break;
 687  }</pre>
 688      </div>
 689  
 690      <p>Even if the break for the default case is not needed, it is sometimes better to include it just for readability and completeness.</p>
 691  
 692      <p>If no break is intended, please add a comment instead. An example:</p>
 693  
 694      <p class="good">// Example with no break </p>
 695      <div class="codebox"><pre>
 696  switch ($mode)
 697  {
 698      case 'mode1':
 699  
 700          // I am doing something here
 701  
 702      // no break here
 703  
 704      case 'mode2':
 705  
 706          // I am doing something completely different here
 707  
 708      break;
 709  
 710      default:
 711  
 712          // Always assume that a case was not caught
 713  
 714      break;
 715  }</pre>
 716      </div>
 717  
 718      <h4>Class Members</h4>
 719      <p>Use the explicit visibility qualifiers <code>public</code>, <code>private</code> and <code>protected</code> for all properties instead of <code>var</code>.
 720  
 721      <p>Place the <code>static</code> qualifier before the visibility qualifiers.</p>
 722  
 723      <p class="bad">//Wrong </p>
 724      <div class="codebox"><pre>
 725  var $x;
 726  private static function f()</pre>
 727      </div>
 728  
 729      <p class="good">// Right </p>
 730      <div class="codebox"><pre>
 731  public $x;
 732  static private function f()</pre>
 733      </div>
 734  
 735      <h4>Constants</h4>
 736      <p>Prefer class constants over global constants created with <code>define()</code>.</p>
 737  
 738      <a name="sql"></a><h3>2.iii. SQL/SQL Layout</h3>
 739  
 740      <h4>Common SQL Guidelines: </h4>
 741      <p>All SQL should be cross-DB compatible, if DB specific SQL is used alternatives must be provided which work on all supported DB's (MySQL3/4/5, MSSQL (7.0 and 2000), PostgreSQL (8.3+), SQLite, Oracle8, ODBC (generalised if possible)).</p>
 742      <p>All SQL commands should utilise the DataBase Abstraction Layer (DBAL)</p>
 743  
 744      <h4>SQL code layout:</h4>
 745      <p>SQL Statements are often unreadable without some formatting, since they tend to be big at times. Though the formatting of sql statements adds a lot to the readability of code. SQL statements should be formatted in the following way, basically writing keywords: </p>
 746  
 747      <div class="codebox"><pre>
 748  $sql = 'SELECT *
 749  &lt;-one tab-&gt;FROM ' . SOME_TABLE . '
 750  &lt;-one tab-&gt;WHERE a = 1
 751  &lt;-two tabs-&gt;AND (b = 2
 752  &lt;-three tabs-&gt;OR b = 3)
 753  &lt;-one tab-&gt;ORDER BY b';</pre>
 754      </div>
 755  
 756      <p>Here the example with the tabs applied:</p>
 757  
 758      <div class="codebox"><pre>
 759  $sql = 'SELECT *
 760      FROM ' . SOME_TABLE . '
 761      WHERE a = 1
 762          AND (b = 2
 763              OR b = 3)
 764      ORDER BY b';</pre>
 765      </div>
 766  
 767      <h4>SQL Quotes: </h4>
 768      <p>Use double quotes where applicable. (The variables in these examples are typecasted to integers beforehand.) Examples: </p>
 769  
 770      <p class="bad">// These are wrong.</p>
 771      <div class="codebox"><pre>
 772  "UPDATE " . SOME_TABLE . " SET something = something_else WHERE a = $b";
 773  
 774  'UPDATE ' . SOME_TABLE . ' SET something = ' . $user_id . ' WHERE a = ' . $something;</pre>
 775      </div>
 776  
 777      <p class="good">// These are right. </p>
 778  
 779      <div class="codebox"><pre>
 780  'UPDATE ' . SOME_TABLE . " SET something = something_else WHERE a = $b";
 781  
 782  'UPDATE ' . SOME_TABLE . " SET something = $user_id WHERE a = $something";</pre>
 783      </div>
 784  
 785      <p>In other words use single quotes where no variable substitution is required or where the variable involved shouldn't appear within double quotes. Otherwise use double quotes.</p>
 786  
 787      <h4>Avoid DB specific SQL: </h4>
 788      <p>The &quot;not equals operator&quot;, as defined by the SQL:2003 standard, is &quot;&lt;&gt;&quot;</p>
 789  
 790      <p class="bad">// This is wrong.</p>
 791      <div class="codebox"><pre>
 792  $sql = 'SELECT *
 793      FROM ' . SOME_TABLE . '
 794      WHERE a != 2';</pre>
 795      </div>
 796  
 797      <p class="good">// This is right. </p>
 798      <div class="codebox"><pre>
 799  $sql = 'SELECT *
 800      FROM ' . SOME_TABLE . '
 801      WHERE a &lt;&gt; 2';</pre>
 802      </div>
 803  
 804      <h4>Common DBAL methods: </h4>
 805  
 806      <h4>sql_escape():</h4>
 807  
 808      <p>Always use <code>$db-&gt;sql_escape()</code> if you need to check for a string within an SQL statement (even if you are sure the variable cannot contain single quotes - never trust your input), for example:</p>
 809  
 810      <div class="codebox"><pre>
 811  $sql = 'SELECT *
 812      FROM ' . SOME_TABLE . "
 813      WHERE username = '" . $db-&gt;sql_escape($username) . "'";</pre>
 814      </div>
 815  
 816      <h4>sql_query_limit():</h4>
 817  
 818      <p>We do not add limit statements to the sql query, but instead use <code>$db-&gt;sql_query_limit()</code>. You basically pass the query, the total number of lines to retrieve and the offset.</p>
 819  
 820      <p><strong>Note: </strong> Since Oracle handles limits differently and because of how we implemented this handling you need to take special care if you use <code>sql_query_limit</code> with an sql query retrieving data from more than one table.</p>
 821  
 822      <p>Make sure when using something like "SELECT x.*, y.jars" that there is not a column named jars in x; make sure that there is no overlap between an implicit column and the explicit columns.</p>
 823  
 824      <h4>sql_build_array():</h4>
 825  
 826      <p>If you need to UPDATE or INSERT data, make use of the <code>$db-&gt;sql_build_array()</code> function. This function already escapes strings and checks other types, so there is no need to do this here. The data to be inserted should go into an array - <code>$sql_ary</code> - or directly within the statement if one or two variables needs to be inserted/updated. An example of an insert statement would be:</p>
 827  
 828      <div class="codebox"><pre>
 829  $sql_ary = array(
 830      'somedata'        =&gt; $my_string,
 831      'otherdata'        =&gt; $an_int,
 832      'moredata'        =&gt; $another_int,
 833  );
 834  
 835  $db-&gt;sql_query('INSERT INTO ' . SOME_TABLE . ' ' . $db-&gt;sql_build_array('INSERT', $sql_ary));</pre>
 836      </div>
 837  
 838      <p>To complete the example, this is how an update statement would look like:</p>
 839  
 840      <div class="codebox"><pre>
 841  $sql_ary = array(
 842      'somedata'        =&gt; $my_string,
 843      'otherdata'        =&gt; $an_int,
 844      'moredata'        =&gt; $another_int,
 845  );
 846  
 847  $sql = 'UPDATE ' . SOME_TABLE . '
 848      SET ' . $db-&gt;sql_build_array('UPDATE', $sql_ary) . '
 849      WHERE user_id = ' . (int) $user_id;
 850  $db-&gt;sql_query($sql);</pre>
 851      </div>
 852  
 853      <p>The <code>$db-&gt;sql_build_array()</code> function supports the following modes: <code>INSERT</code> (example above), <code>INSERT_SELECT</code> (building query for <code>INSERT INTO table (...) SELECT value, column ...</code> statements), <code>UPDATE</code> (example above) and <code>SELECT</code> (for building WHERE statement [AND logic]).</p>
 854  
 855      <h4>sql_multi_insert():</h4>
 856  
 857      <p>If you want to insert multiple statements at once, please use the separate <code>sql_multi_insert()</code> method. An example:</p>
 858  
 859      <div class="codebox"><pre>
 860  $sql_ary = array();
 861  
 862  $sql_ary[] = array(
 863      'somedata'        =&gt; $my_string_1,
 864      'otherdata'        =&gt; $an_int_1,
 865      'moredata'        =&gt; $another_int_1,
 866  );
 867  
 868  $sql_ary[] = array(
 869      'somedata'        =&gt; $my_string_2,
 870      'otherdata'        =&gt; $an_int_2,
 871      'moredata'        =&gt; $another_int_2,
 872  );
 873  
 874  $db->sql_multi_insert(SOME_TABLE, $sql_ary);</pre>
 875      </div>
 876  
 877      <h4>sql_in_set():</h4>
 878  
 879      <p>The <code>$db-&gt;sql_in_set()</code> function should be used for building <code>IN ()</code> and <code>NOT IN ()</code> constructs. Since (specifically) MySQL tend to be faster if for one value to be compared the <code>=</code> and <code>&lt;&gt;</code> operator is used, we let the DBAL decide what to do. A typical example of doing a positive match against a number of values would be:</p>
 880  
 881      <div class="codebox"><pre>
 882  $sql = 'SELECT *
 883      FROM ' . FORUMS_TABLE . '
 884      WHERE ' . $db-&gt;sql_in_set('forum_id', $forum_ids);
 885  $db-&gt;sql_query($sql);</pre>
 886      </div>
 887  
 888      <p>Based on the number of values in $forum_ids, the query can look differently.</p>
 889  
 890      <p class="good">// SQL Statement if $forum_ids = array(1, 2, 3);</p>
 891  
 892      <div class="codebox"><pre>
 893  SELECT FROM phpbb_forums WHERE forum_id IN (1, 2, 3)</pre>
 894      </div>
 895  
 896      <p class="good">// SQL Statement if $forum_ids = array(1) or $forum_ids = 1</p>
 897  
 898      <div class="codebox"><pre>
 899  SELECT FROM phpbb_forums WHERE forum_id = 1</pre>
 900      </div>
 901  
 902      <p>Of course the same is possible for doing a negative match against a number of values:</p>
 903  
 904      <div class="codebox"><pre>
 905  $sql = 'SELECT *
 906      FROM ' . FORUMS_TABLE . '
 907      WHERE ' . $db-&gt;sql_in_set('forum_id', $forum_ids, <strong>true</strong>);
 908  $db-&gt;sql_query($sql);</pre>
 909      </div>
 910  
 911      <p>Based on the number of values in $forum_ids, the query can look differently here too.</p>
 912  
 913      <p class="good">// SQL Statement if $forum_ids = array(1, 2, 3);</p>
 914  
 915      <div class="codebox"><pre>
 916  SELECT FROM phpbb_forums WHERE forum_id <strong>NOT</strong> IN (1, 2, 3)</pre>
 917      </div>
 918  
 919      <p class="good">// SQL Statement if $forum_ids = array(1) or $forum_ids = 1</p>
 920  
 921      <div class="codebox"><pre>
 922  SELECT FROM phpbb_forums WHERE forum_id <strong>&lt;&gt;</strong> 1</pre>
 923      </div>
 924  
 925      <p>If the given array is empty, an error will be produced.</p>
 926  
 927      <h4>sql_build_query():</h4>
 928  
 929      <p>The <code>$db-&gt;sql_build_query()</code> function is responsible for building sql statements for SELECT and SELECT DISTINCT queries if you need to JOIN on more than one table or retrieve data from more than one table while doing a JOIN. This needs to be used to make sure the resulting statement is working on all supported db's. Instead of explaining every possible combination, I will give a short example:</p>
 930  
 931      <div class="codebox"><pre>
 932  $sql_array = array(
 933      'SELECT'    =&gt; 'f.*, ft.mark_time',
 934  
 935      'FROM'        =&gt; array(
 936          FORUMS_WATCH_TABLE    =&gt; 'fw',
 937          FORUMS_TABLE        =&gt; 'f',
 938      ),
 939  
 940      'LEFT_JOIN'    =&gt; array(
 941          array(
 942              'FROM'    =&gt; array(FORUMS_TRACK_TABLE =&gt; 'ft'),
 943              'ON'    =&gt; 'ft.user_id = ' . $user-&gt;data['user_id'] . ' AND ft.forum_id = f.forum_id',
 944          ),
 945      ),
 946  
 947      'WHERE'        =&gt; 'fw.user_id = ' . $user-&gt;data['user_id'] . '
 948          AND f.forum_id = fw.forum_id',
 949  
 950      'ORDER_BY'    =&gt; 'left_id',
 951  );
 952  
 953  $sql = $db-&gt;sql_build_query('SELECT', $sql_array);</pre>
 954      </div>
 955  
 956      <p>The possible first parameter for sql_build_query() is SELECT or SELECT_DISTINCT. As you can see, the logic is pretty self-explaining. For the LEFT_JOIN key, just add another array if you want to join on to tables for example. The added benefit of using this construct is that you are able to easily build the query statement based on conditions - for example the above LEFT_JOIN is only necessary if server side topic tracking is enabled; a slight adjustement would be:</p>
 957  
 958      <div class="codebox"><pre>
 959  $sql_array = array(
 960      'SELECT'    =&gt; 'f.*',
 961  
 962      'FROM'        =&gt; array(
 963          FORUMS_WATCH_TABLE    =&gt; 'fw',
 964          FORUMS_TABLE        =&gt; 'f',
 965      ),
 966  
 967      'WHERE'        =&gt; 'fw.user_id = ' . $user-&gt;data['user_id'] . '
 968          AND f.forum_id = fw.forum_id',
 969  
 970      'ORDER_BY'    =&gt; 'left_id',
 971  );
 972  
 973  if ($config['load_db_lastread'])
 974  {
 975      $sql_array['LEFT_JOIN'] = array(
 976          array(
 977              'FROM'    =&gt; array(FORUMS_TRACK_TABLE =&gt; 'ft'),
 978              'ON'    =&gt; 'ft.user_id = ' . $user-&gt;data['user_id'] . ' AND ft.forum_id = f.forum_id',
 979          ),
 980      );
 981  
 982      $sql_array['SELECT'] .= ', ft.mark_time ';
 983  }
 984  else
 985  {
 986      // Here we read the cookie data
 987  }
 988  
 989  $sql = $db-&gt;sql_build_query('SELECT', $sql_array);</pre>
 990      </div>
 991  
 992      <a name="optimizing"></a><h3>2.iv. Optimizations</h3>
 993  
 994      <h4>Operations in loop definition: </h4>
 995      <p>Always try to optimize your loops if operations are going on at the comparing part, since this part is executed every time the loop is parsed through. For assignments a descriptive name should be chosen. Example:</p>
 996  
 997      <p class="bad">// On every iteration the sizeof function is called</p>
 998      <div class="codebox"><pre>
 999  for ($i = 0; $i &lt; sizeof($post_data); $i++)
1000  {
1001      do_something();
1002  }</pre>
1003      </div>
1004  
1005      <p class="good">// You are able to assign the (not changing) result within the loop itself</p>
1006      <div class="codebox"><pre>
1007  for ($i = 0, $size = sizeof($post_data); $i &lt; $size; $i++)
1008  {
1009      do_something();
1010  }</pre>
1011      </div>
1012  
1013      <h4>Use of in_array(): </h4>
1014      <p>Try to avoid using in_array() on huge arrays, and try to not place them into loops if the array to check consist of more than 20 entries. in_array() can be very time consuming and uses a lot of cpu processing time. For little checks it is not noticeable, but if checked against a huge array within a loop those checks alone can take several seconds. If you need this functionality, try using isset() on the arrays keys instead, actually shifting the values into keys and vice versa. A call to <code>isset($array[$var])</code> is a lot faster than <code>in_array($var, array_keys($array))</code> for example.</p>
1015  
1016  
1017      <a name="general"></a><h3>2.v. General Guidelines</h3>
1018  
1019      <h4>General things:</h4>
1020      <p>Never trust user input (this also applies to server variables as well as cookies).</p>
1021      <p>Try to sanitize values returned from a function.</p>
1022      <p>Try to sanitize given function variables within your function.</p>
1023      <p>The auth class should be used for all authorisation checking.</p>
1024      <p>No attempt should be made to remove any copyright information (either contained within the source or displayed interactively when the source is run/compiled), neither should the copyright information be altered in any way (it may be added to).</p>
1025  
1026      <h4>Variables: </h4>
1027      <p>Make use of the <code>\phpbb\request\request</code> class for everything.</p>
1028      <p>The $request->variable() method determines the type to set from the second parameter (which determines the default value too). If you need to get a scalar variable type, you need to tell this the variable() method explicitly. Examples:</p>
1029  
1030      <p class="bad">// Old method, do not use it</p>
1031      <div class="codebox"><pre>
1032  $start = (isset($HTTP_GET_VARS['start'])) ? intval($HTTP_GET_VARS['start']) : intval($HTTP_POST_VARS['start']);
1033  $submit = (isset($HTTP_POST_VARS['submit'])) ? true : false;</pre>
1034      </div>
1035  
1036      <p class="good">// Use request var and define a default variable (use the correct type)</p>
1037      <div class="codebox"><pre>
1038  $start = $request->variable('start', 0);
1039  $submit = $request->is_set_post('submit');</pre>
1040      </div>
1041  
1042      <p class="bad">// $start is an int, the following use of $request->variable() therefore is not allowed</p>
1043      <div class="codebox"><pre>
1044  $start = $request->variable('start', '0');</pre>
1045      </div>
1046  
1047      <p class="good">// Getting an array, keys are integers, value defaults to 0</p>
1048      <div class="codebox"><pre>
1049  $mark_array = $request->variable('mark', array(0));</pre>
1050      </div>
1051  
1052      <p class="good">// Getting an array, keys are strings, value defaults to 0</p>
1053      <div class="codebox"><pre>
1054  $action_ary = $request->variable('action', array('' =&gt; 0));</pre>
1055      </div>
1056  
1057      <h4>Login checks/redirection: </h4>
1058      <p>To show a forum login box use <code>login_forum_box($forum_data)</code>, else use the <code>login_box()</code> function.</p>
1059  
1060      <p><code>$forum_data</code> should contain at least the <code>forum_id</code> and <code>forum_password</code> fields. If the field <code>forum_name</code> is available, then it is displayed on the forum login page.</p>
1061  
1062      <p>The <code>login_box()</code> function can have a redirect as the first parameter. As a thumb of rule, specify an empty string if you want to redirect to the users current location, else do not add the <code>$SID</code> to the redirect string (for example within the ucp/login we redirect to the board index because else the user would be redirected to the login screen).</p>
1063  
1064      <h4>Sensitive Operations: </h4>
1065      <p>For sensitive operations always let the user confirm the action. For the confirmation screens, make use of the <code>confirm_box()</code> function.</p>
1066  
1067      <h4>Altering Operations: </h4>
1068      <p>For operations altering the state of the database, for instance posting, always verify the form token, unless you are already using <code>confirm_box()</code>. To do so, make use of the <code>add_form_key()</code> and <code>check_form_key()</code> functions. </p>
1069      <div class="codebox"><pre>
1070      add_form_key('my_form');
1071  
1072      if ($submit)
1073      {
1074          if (!check_form_key('my_form'))
1075          {
1076              trigger_error('FORM_INVALID');
1077          }
1078      }</pre>
1079      </div>
1080  
1081      <p>The string passed to <code>add_form_key()</code> needs to match the string passed to <code>check_form_key()</code>. Another requirement for this to work correctly is that all forms include the <code>{S_FORM_TOKEN}</code> template variable.</p>
1082  
1083  
1084      <h4>Sessions: </h4>
1085      <p>Sessions should be initiated on each page, as near the top as possible using the following code:</p>
1086  
1087      <div class="codebox"><pre>
1088  $user-&gt;session_begin();
1089  $auth-&gt;acl($user-&gt;data);
1090  $user-&gt;setup();</pre>
1091      </div>
1092  
1093      <p>The <code>$user-&gt;setup()</code> call can be used to pass on additional language definition and a custom style (used in viewforum).</p>
1094  
1095      <h4>Errors and messages: </h4>
1096      <p>All messages/errors should be outputted by calling <code>trigger_error()</code> using the appropriate message type and language string. Example:</p>
1097  
1098      <div class="codebox"><pre>
1099  trigger_error('NO_FORUM');</pre>
1100      </div>
1101  
1102      <div class="codebox"><pre>
1103  trigger_error($user-&gt;lang['NO_FORUM']);</pre>
1104      </div>
1105  
1106      <div class="codebox"><pre>
1107  trigger_error('NO_MODE', E_USER_ERROR);</pre>
1108      </div>
1109  
1110      <h4>Url formatting</h4>
1111  
1112      <p>All urls pointing to internal files need to be prepended by the <code>$phpbb_root_path</code> variable. Within the administration control panel all urls pointing to internal files need to be prepended by the <code>$phpbb_admin_path</code> variable. This makes sure the path is always correct and users being able to just rename the admin folder and the acp still working as intended (though some links will fail and the code need to be slightly adjusted).</p>
1113  
1114      <p>The <code>append_sid()</code> function from 2.0.x is available too, though it does not handle url alterations automatically. Please have a look at the code documentation if you want to get more details on how to use append_sid(). A sample call to append_sid() can look like this:</p>
1115  
1116      <div class="codebox"><pre>
1117  append_sid(&quot;{$phpbb_root_path}memberlist.$phpEx&quot;, 'mode=group&amp;amp;g=' . $row['group_id'])</pre>
1118      </div>
1119  
1120      <h4>General function usage: </h4>
1121  
1122      <p>Some of these functions are only chosen over others because of personal preference and have no benefit other than maintaining consistency throughout the code.</p>
1123  
1124      <ul>
1125          <li>
1126              <p>Use <code>sizeof</code> instead of <code>count</code></p>
1127          </li>
1128          <li>
1129              <p>Use <code>strpos</code> instead of <code>strstr</code></p>
1130          </li>
1131          <li>
1132              <p>Use <code>else if</code> instead of <code>elseif</code></p>
1133          </li>
1134          <li>
1135              <p>Use <code>false</code> (lowercase) instead of <code>FALSE</code></p>
1136          </li>
1137          <li>
1138              <p>Use <code>true</code> (lowercase) instead of <code>TRUE</code></p>
1139          </li>
1140      </ul>
1141  
1142      <h4>Exiting</h4>
1143  
1144      <p>Your page should either call <code>page_footer()</code> in the end to trigger output through the template engine and terminate the script, or alternatively at least call the <code>exit_handler()</code>. That call is necessary because it provides a method for external applications embedding phpBB to be called at the end of the script.</p>
1145  
1146      <a name="phprestrictions"></a><h3>2.vi. Restrictions on the Use of PHP</h3>
1147  
1148      <h4>Dynamic code execution:</h4>
1149  
1150      <p>Never execute dynamic PHP code (generated or in a constant string) using any of the following PHP functions:</p>
1151  
1152      <ul>
1153          <li><strong>eval</strong></li>
1154          <li><strong>create_function</strong></li>
1155          <li><strong>preg_replace</strong> with the <strong>e</strong> modifier in the pattern</li>
1156      </ul>
1157  
1158      <p>If absolutely necessary a file should be created, and a mechanism for creating this file prior to running phpBB should be provided as a setup process.</p>
1159  
1160      <p>The <strong>e</strong> modifier in <strong>preg_replace</strong> can be replaced by <strong>preg_replace_callback</strong> and objects to encapsulate state that is needed in the callback code.</p>
1161  
1162      <h4>Other functions, operators, statements and keywords:</h4>
1163  
1164      <p>The following PHP statements should also not be used in phpBB:</p>
1165  
1166      <ul>
1167          <li><strong>goto</strong></li>
1168      </ul>
1169  
1170          </div>
1171  
1172          <div class="back2top"><a href="#wrap" class="top">Back to Top</a></div>
1173  
1174          </div>
1175      </div>
1176  
1177      <hr />
1178  
1179  <a name="styling"></a><h2>3. Styling</h2>
1180      <div class="paragraph">
1181          <div class="inner">
1182  
1183          <div class="content">
1184      <a name="cfgfiles"></a><h3>3.i. Style Config Files</h3>
1185      <p>Style cfg files are simple name-value lists with the information necessary for installing a style. The important part of the style configuration file is assigning an unique name.</p>
1186      <div class="codebox"><pre>
1187  # General Information about this style
1188  name = prosilver_duplicate
1189  copyright = © phpBB Limited, 2007
1190  style_version = 3.1.0
1191  phpbb_version = 3.1.0
1192  
1193  # Defining a different template bitfield
1194  # template_bitfield = lNg=
1195  
1196  # Parent style
1197  # Set value to empty or to this style's name if this style does not have a parent style
1198  parent = prosilver</pre>
1199      </div>
1200      <a name="genstyling"></a><h3>3.2. General Styling Rules</h3>
1201  <p>Templates should be produced in a consistent manner. Where appropriate they should be based off an existing copy, e.g. index, viewforum or viewtopic (the combination of which implement a range of conditional and variable forms). Please also note that the indentation and coding guidelines also apply to templates where possible.</p>
1202  
1203  <p>The outer table class <code>forumline</code> has gone and is replaced with <code>tablebg</code>.</p>
1204  <p>When writing <code>&lt;table&gt;</code> the order <code>&lt;table class="" cellspacing="" cellpadding="" border="" align=""&gt;</code> creates consistency and allows everyone to easily see which table produces which "look". The same applies to most other tags for which additional parameters can be set, consistency is the major aim here.</p>
1205  <p>Each block level element should be indented by one tab, same for tabular elements, e.g. <code>&lt;tr&gt;</code> <code>&lt;td&gt;</code> etc., whereby the intendiation of <code>&lt;table&gt;</code> and the following/ending <code>&lt;tr&gt;</code> should be on the same line. This applies not to div elements of course.</p>
1206  <p>Don't use <code>&lt;span&gt;</code> more than is essential ... the CSS is such that text sizes are dependent on the parent class. So writing <code>&lt;span class="gensmall"&gt;&lt;span class="gensmall"&gt;TEST&lt;/span&gt;&lt;/span&gt;</code> will result in very very small text. Similarly don't use span at all if another element can contain the class definition, e.g.</p>
1207  
1208  <div class="codebox"><pre>
1209  &lt;td&gt;&lt;span class=&quot;gensmall&quot;&gt;TEST&lt;/span&gt;&lt;/td&gt;
1210  </pre></div>
1211  
1212  <p>can just as well become:</p>
1213  <div class="codebox"><pre>
1214  &lt;td class=&quot;gensmall&quot;&gt;TEST&lt;/td&gt;
1215  </pre></div>
1216  
1217  <p>Try to match text class types with existing useage, e.g. don't use the nav class where viewtopic uses gensmall for example.</p>
1218  
1219  <p>Row colours/classes are now defined by the template, use an <code>IF S_ROW_COUNT</code> switch, see viewtopic or viewforum for an example.</p>
1220  
1221  <p>Remember block level ordering is important.</p>
1222  
1223  <p>Use a standard cellpadding of 2 and cellspacing of 0 on outer tables. Inner tables can vary from 0 to 3 or even 4 depending on the need.</p>
1224  
1225  <p><strong>Use div container/css for styling and table for data representation.</strong></p>
1226  
1227  <p>The separate catXXXX and thXXX classes are gone. When defining a header cell just use <code>&lt;th&gt;</code> rather than <code>&lt;th class="thHead"&gt;</code> etc. Similarly for cat, don't use <code>&lt;td class="catLeft"&gt;</code> use <code>&lt;td class="cat"&gt;</code> etc.</p>
1228  
1229  <p>Try to retain consistency of basic layout and class useage, i.e. _EXPLAIN text should generally be placed below the title it explains, e.g. <code>{L_POST_USERNAME}&lt;br /&gt;&lt;span class="gensmall"&gt;{L_POST_USERNAME_EXPLAIN}&lt;/span&gt;</code> is the typical way of handling this ... there may be exceptions and this isn't a hard and fast rule.</p>
1230  
1231  <p>Try to keep template conditional and other statements tabbed in line with the block to which they refer.</p>
1232  
1233  <p class="good">this is correct</p>
1234  <div class="codebox"><pre>
1235  <span class="comment">&lt;!-- BEGIN test --&gt;</span>
1236      &lt;tr&gt;
1237          &lt;td&gt;&#123;test.TEXT&#125;&lt;/td&gt;
1238      &lt;/tr&gt;
1239  <span class="comment">&lt;!-- END test --&gt;</span>
1240  </pre></div>
1241  
1242  <p class="good">this is also correct:</p>
1243  <div class="codebox"><pre>
1244  <span class="comment">&lt;!-- BEGIN test --&gt;</span>
1245  &lt;tr&gt;
1246      &lt;td&gt;&#123;test.TEXT&#125;&lt;/td&gt;
1247  &lt;/tr&gt;
1248  <span class="comment">&lt;!-- END test --&gt;</span>
1249  </pre></div>
1250  
1251  <p>it gives immediate feedback on exactly what is looping - decide which way to use based on the readability.</p>
1252  
1253          </div>
1254  
1255          <div class="back2top"><a href="#wrap" class="top">Back to Top</a></div>
1256  
1257          </div>
1258      </div>
1259  
1260      <hr />
1261  
1262  <a name="templating"></a><h2>4. Templating</h2>
1263      <div class="paragraph">
1264          <div class="inner">
1265  
1266          <div class="content">
1267      <a name="templates"></a><h3>4.i. General Templating</h3>
1268  
1269  <h4>File naming</h4>
1270  <p>Firstly templates now take the suffix &quot;.html&quot; rather than &quot;.tpl&quot;. This was done simply to make the lives of some people easier wrt syntax highlighting, etc.</p>
1271  
1272  <h4>Variables</h4>
1273  <p>All template variables should be named appropriately (using underscores for spaces), language entries should be prefixed with L_, system data with S_, urls with U_, javascript urls with UA_, language to be put in javascript statements with LA_, all other variables should be presented 'as is'.</p>
1274  
1275  <p>L_* template variables are automatically mapped to the corresponding language entry if the code does not set (and therefore overwrite) this variable specifically and if the language entry exists. For example <code>{L_USERNAME}</code> maps to <code>$user-&gt;lang['USERNAME']</code>. The LA_* template variables are handled within the same way, but properly escaped so they can be put in javascript code. This should reduce the need to assign loads of new language variables in MODifications.
1276  </p>
1277  
1278  <h4>Blocks/Loops</h4>
1279  <p>The basic block level loop remains and takes the form:</p>
1280  <div class="codebox"><pre>
1281  <span class="comment">&lt;!-- BEGIN loopname --&gt;</span>
1282      markup, {loopname&#46;X_YYYYY}, etc&#46;
1283  <span class="comment">&lt;!-- END loopname --&gt;</span>
1284  </pre></div>
1285  
1286  <p>A bit later loops will be explained further. To not irritate you we will explain conditionals as well as other statements first.</p>
1287  
1288  <h4>Including files</h4>
1289  <p>Something that existed in 2.0.x which no longer exists in 3.x is the ability to assign a template to a variable. This was used (for example) to output the jumpbox. Instead (perhaps better, perhaps not but certainly more flexible) we now have INCLUDE. This takes the simple form:</p>
1290  
1291  <div class="codebox"><pre>
1292  <span class="comment">&lt;!-- INCLUDE filename --&gt;</span>
1293  </pre></div>
1294  
1295  <p>You will note in the 3.x templates the major sources start with <code>&lt;!-- INCLUDE overall_header.html --&gt;</code> or <code>&lt;!-- INCLUDE simple_header.html --&gt;</code>, etc. In 2.0.x control of &quot;which&quot; header to use was defined entirely within the code. In 3.x the template designer can output what they like. Note that you can introduce new templates (i.e. other than those in the default set) using this system and include them as you wish ... perhaps useful for a common &quot;menu&quot; bar or some such. No need to modify loads of files as with 2.0.x.</p>
1296  
1297  <p>Added in <strong>3.0.6</strong> is the ability to include a file using a template variable to specify the file, this functionality only works for root variables (i.e. not block variables).</p>
1298  <div class="codebox"><pre>
1299  <span class="comment">&lt;!-- INCLUDE {FILE_VAR} --&gt;</span>
1300  </pre></div>
1301  
1302  <p>Template defined variables can also be utilised.</p>
1303  
1304  <div class="codebox"><pre>
1305  <span class="comment">&lt;!-- DEFINE $SOME_VAR = 'my_file.html' --&gt;</span>
1306  <span class="comment">&lt;!-- INCLUDE {$SOME_VAR} --&gt;</span>
1307  </pre></div>
1308  
1309  <h4>PHP</h4>
1310  <p>A contentious decision has seen the ability to include PHP within the template introduced. This is achieved by enclosing the PHP within relevant tags:</p>
1311  
1312  <div class="codebox"><pre>
1313  <span class="comment">&lt;!-- PHP --&gt;</span>
1314      echo &quot;hello!&quot;;
1315  <span class="comment">&lt;!-- ENDPHP --&gt;</span>
1316  </pre></div>
1317  
1318  <p>You may also include PHP from an external file using:</p>
1319  
1320  <div class="codebox"><pre>
1321  <span class="comment">&lt;!-- INCLUDEPHP somefile&#46;php --&gt;</span>
1322  </pre></div>
1323  
1324  <p>it will be included and executed inline.<br /><br />A note, it is very much encouraged that template designers do not include PHP. The ability to include raw PHP was introduced primarily to allow end users to include banner code, etc. without modifying multiple files (as with 2.0.x). It was not intended for general use ... hence <!-- w --><a href="https://www.phpbb.com">www.phpbb.com</a><!-- w --> will <strong>not</strong> make available template sets which include PHP. And by default templates will have PHP disabled (the admin will need to specifically activate PHP for a template).</p>
1325  
1326  <h4>Conditionals/Control structures</h4>
1327  <p>The most significant addition to 3.x are conditions or control structures, &quot;if something then do this else do that&quot;. The system deployed is very similar to Smarty. This may confuse some people at first but it offers great potential and great flexibility with a little imagination. In their most simple form these constructs take the form:</p>
1328  
1329  <div class="codebox"><pre>
1330  <span class="comment">&lt;!-- IF expr --&gt;</span>
1331      markup
1332  <span class="comment">&lt;!-- ENDIF --&gt;</span>
1333  </pre></div>
1334  
1335  <p>expr can take many forms, for example:</p>
1336  
1337  <div class="codebox"><pre>
1338  <span class="comment">&lt;!-- IF loop&#46;S_ROW_COUNT is even --&gt;</span>
1339      markup
1340  <span class="comment">&lt;!-- ENDIF --&gt;</span>
1341  </pre></div>
1342  
1343  <p>This will output the markup if the S_ROW_COUNT variable in the current iteration of loop is an even value (i.e. the expr is TRUE). You can use various comparison methods (standard as well as equivalent textual versions noted in square brackets) including (<code>not, or, and, eq, neq, is</code> should be used if possible for better readability):</p>
1344  
1345  <div class="codebox"><pre>
1346  == [eq]
1347  != [neq, ne]
1348  &lt;&gt; (same as !=)
1349  !== (not equivalent in value and type)
1350  === (equivalent in value and type)
1351  &gt; [gt]
1352  &lt; [lt]
1353  &gt;= [gte]
1354  &lt;= [lte]
1355  &amp;&amp; [and]
1356  || [or]
1357  % [mod]
1358  ! [not]
1359  +
1360  -
1361  *
1362  /
1363  ,
1364  &lt;&lt; (bitwise shift left)
1365  &gt;&gt; (bitwise shift right)
1366  | (bitwise or)
1367  ^ (bitwise xor)
1368  &amp; (bitwise and)
1369  ~ (bitwise not)
1370  is (can be used to join comparison operations)
1371  </pre></div>
1372  
1373  <p>Basic parenthesis can also be used to enforce good old BODMAS rules. Additionally some basic comparison types are defined:</p>
1374  
1375  <div class="codebox"><pre>
1376  even
1377  odd
1378  div
1379  </pre></div>
1380  
1381  <p>Beyond the simple use of IF you can also do a sequence of comparisons using the following:</p>
1382  
1383  <div class="codebox"><pre>
1384  <span class="comment">&lt;!-- IF expr1 --&gt;</span>
1385      markup
1386  <span class="comment">&lt;!-- ELSEIF expr2 --&gt;</span>
1387      markup
1388      &#46;
1389      &#46;
1390      &#46;
1391  <span class="comment">&lt;!-- ELSEIF exprN --&gt;</span>
1392      markup
1393  <span class="comment">&lt;!-- ELSE --&gt;</span>
1394      markup
1395  <span class="comment">&lt;!-- ENDIF --&gt;</span>
1396  </pre></div>
1397  
1398  <p>Each statement will be tested in turn and the relevant output generated when a match (if a match) is found. It is not necessary to always use ELSEIF, ELSE can be used alone to match &quot;everything else&quot;.<br /><br />So what can you do with all this? Well take for example the colouration of rows in viewforum. In 2.0.x row colours were predefined within the source as either row color1, row color2 or row class1, row class2. In 3.x this is moved to the template, it may look a little daunting at first but remember control flows from top to bottom and it's not too difficult:</p>
1399  
1400  <div class="codebox"><pre>
1401  &lt;table&gt;
1402      <span class="comment">&lt;!-- IF loop&#46;S_ROW_COUNT is even --&gt;</span>
1403          &lt;tr class=&quot;row1&quot;&gt;
1404      <span class="comment">&lt;!-- ELSE --&gt;</span>
1405          &lt;tr class=&quot;row2&quot;&gt;
1406      <span class="comment">&lt;!-- ENDIF --&gt;</span>
1407      &lt;td&gt;HELLO!&lt;/td&gt;
1408  &lt;/tr&gt;
1409  &lt;/table&gt;
1410  </pre></div>
1411  
1412  <p>This will cause the row cell to be output using class row1 when the row count is even, and class row2 otherwise. The S_ROW_COUNT parameter gets assigned to loops by default. Another example would be the following: </p>
1413  
1414  <div class="codebox"><pre>
1415  &lt;table&gt;
1416      <span class="comment">&lt;!-- IF loop&#46;S_ROW_COUNT &gt; 10 --&gt;</span>
1417          &lt;tr bgcolor=&quot;#FF0000&quot;&gt;
1418      <span class="comment">&lt;!-- ELSEIF loop&#46;S_ROW_COUNT &gt; 5 --&gt;</span>
1419          &lt;tr bgcolor=&quot;#00FF00&quot;&gt;
1420      <span class="comment">&lt;!-- ELSEIF loop&#46;S_ROW_COUNT &gt; 2 --&gt;</span>
1421          &lt;tr bgcolor=&quot;#0000FF&quot;&gt;
1422      <span class="comment">&lt;!-- ELSE --&gt;</span>
1423          &lt;tr bgcolor=&quot;#FF00FF&quot;&gt;
1424      <span class="comment">&lt;!-- ENDIF --&gt;</span>
1425      &lt;td&gt;hello!&lt;/td&gt;
1426  &lt;/tr&gt;
1427  &lt;/table&gt;
1428  </pre></div>
1429  
1430  <p>This will output the row cell in purple for the first two rows, blue for rows 2 to 5, green for rows 5 to 10 and red for remainder. So, you could produce a &quot;nice&quot; gradient effect, for example.<br /><br />What else can you do? Well, you could use IF to do common checks on for example the login state of a user:</p>
1431  
1432  <div class="codebox"><pre>
1433  <span class="comment">&lt;!-- IF S_USER_LOGGED_IN --&gt;</span>
1434      markup
1435  <span class="comment">&lt;!-- ENDIF --&gt;</span>
1436  </pre></div>
1437  
1438  <p>This replaces the existing (fudged) method in 2.0.x using a zero length array and BEGIN/END.</p>
1439  
1440  <h4>Extended syntax for Blocks/Loops</h4>
1441  
1442  <p>Back to our loops - they had been extended with the following additions. Firstly you can set the start and end points of the loop. For example:</p>
1443  
1444  <div class="codebox"><pre>
1445  <span class="comment">&lt;!-- BEGIN loopname(2) --&gt;</span>
1446      markup
1447  <span class="comment">&lt;!-- END loopname --&gt;</span>
1448  </pre></div>
1449  
1450  <p>Will start the loop on the third entry (note that indexes start at zero). Extensions of this are:
1451  <br /><br />
1452  <code>loopname(2)</code>: Will start the loop on the 3rd entry<br />
1453  <code>loopname(-2)</code>: Will start the loop two entries from the end<br />
1454  <code>loopname(3,4)</code>: Will start the loop on the fourth entry and end it on the fifth<br />
1455  <code>loopname(3,-4)</code>: Will start the loop on the fourth entry and end it four from last<br />
1456  </p>
1457  
1458  <p>A further extension to begin is BEGINELSE:</p>
1459  
1460  <div class="codebox"><pre>
1461  <span class="comment">&lt;!-- BEGIN loop --&gt;</span>
1462      markup
1463  <span class="comment">&lt;!-- BEGINELSE --&gt;</span>
1464      markup
1465  <span class="comment">&lt;!-- END loop --&gt;</span>
1466  </pre></div>
1467  
1468  <p>This will cause the markup between <code>BEGINELSE</code> and <code>END</code> to be output if the loop contains no values. This is useful for forums with no topics (for example) ... in some ways it replaces &quot;bits of&quot; the existing &quot;switch_&quot; type control (the rest being replaced by conditionals).</p>
1469  
1470  <p>Another way of checking if a loop contains values is by prefixing the loops name with a dot:</p>
1471  
1472  <div class="codebox"><pre>
1473  <span class="comment">&lt;!-- IF .loop --&gt;</span>
1474      <span class="comment">&lt;!-- BEGIN loop --&gt;</span>
1475          markup
1476      <span class="comment">&lt;!-- END loop --&gt;</span>
1477  <span class="comment">&lt;!-- ELSE --&gt;</span>
1478      markup
1479  <span class="comment">&lt;!-- ENDIF --&gt;</span>
1480  </pre></div>
1481  
1482  <p>You are even able to check the number of items within a loop by comparing it with values within the IF condition:</p>
1483  
1484  <div class="codebox"><pre>
1485  <span class="comment">&lt;!-- IF .loop &gt; 2 --&gt;</span>
1486      <span class="comment">&lt;!-- BEGIN loop --&gt;</span>
1487          markup
1488      <span class="comment">&lt;!-- END loop --&gt;</span>
1489  <span class="comment">&lt;!-- ELSE --&gt;</span>
1490      markup
1491  <span class="comment">&lt;!-- ENDIF --&gt;</span>
1492  </pre></div>
1493  
1494  <p>Nesting loops cause the conditionals needing prefixed with all loops from the outer one to the inner most. An illustration of this:</p>
1495  
1496  <div class="codebox"><pre>
1497  <span class="comment">&lt;!-- BEGIN firstloop --&gt;</span>
1498      {firstloop.MY_VARIABLE_FROM_FIRSTLOOP}
1499  
1500      <span class="comment">&lt;!-- BEGIN secondloop --&gt;</span>
1501          {firstloop.secondloop.MY_VARIABLE_FROM_SECONDLOOP}
1502      <span class="comment">&lt;!-- END secondloop --&gt;</span>
1503  <span class="comment">&lt;!-- END firstloop --&gt;</span>
1504  </pre></div>
1505  
1506  <p>Sometimes it is necessary to break out of nested loops to be able to call another loop within the current iteration. This sounds a little bit confusing and it is not used very often. The following (rather complex) example shows this quite good - it also shows how you test for the first and last row in a loop (i will explain the example in detail further down):</p>
1507  
1508  <div class="codebox"><pre>
1509  <span class="comment">&lt;!-- BEGIN l_block1 --&gt;</span>
1510      <span class="comment">&lt;!-- IF l_block1.S_SELECTED --&gt;</span>
1511          &lt;strong&gt;{l_block1.L_TITLE}&lt;/strong&gt;
1512          <span class="comment">&lt;!-- IF S_PRIVMSGS --&gt;</span>
1513  
1514              <span class="comment">&lt;!-- the ! at the beginning of the loop name forces the loop to be not a nested one of l_block1 --&gt;</span>
1515              <span class="comment">&lt;!-- BEGIN !folder --&gt;</span>
1516                  <span class="comment">&lt;!-- IF folder.S_FIRST_ROW --&gt;</span>
1517                      &lt;ul class=&quot;nav&quot;&gt;
1518                  <span class="comment">&lt;!-- ENDIF --&gt;</span>
1519  
1520                  &lt;li&gt;&lt;a href=&quot;{folder.U_FOLDER}&quot;&gt;{folder.FOLDER_NAME}&lt;/a&gt;&lt;/li&gt;
1521  
1522                  <span class="comment">&lt;!-- IF folder.S_LAST_ROW --&gt;</span>
1523                      &lt;/ul&gt;
1524                  <span class="comment">&lt;!-- ENDIF --&gt;</span>
1525              <span class="comment">&lt;!-- END !folder --&gt;</span>
1526  
1527          <span class="comment">&lt;!-- ENDIF --&gt;</span>
1528  
1529          &lt;ul class=&quot;nav&quot;&gt;
1530          <span class="comment">&lt;!-- BEGIN l_block2 --&gt;</span>
1531              &lt;li&gt;
1532                  <span class="comment">&lt;!-- IF l_block1.l_block2.S_SELECTED --&gt;</span>
1533                      &lt;strong&gt;{l_block1.l_block2.L_TITLE}&lt;/strong&gt;
1534                  <span class="comment">&lt;!-- ELSE --&gt;</span>
1535                      &lt;a href=&quot;{l_block1.l_block2.U_TITLE}&quot;&gt;{l_block1.l_block2.L_TITLE}&lt;/a&gt;
1536                  <span class="comment">&lt;!-- ENDIF --&gt;</span>
1537              &lt;/li&gt;
1538          <span class="comment">&lt;!-- END l_block2 --&gt;</span>
1539          &lt;/ul&gt;
1540      <span class="comment">&lt;!-- ELSE --&gt;</span>
1541          &lt;a class=&quot;nav&quot; href=&quot;{l_block1.U_TITLE}&quot;&gt;{l_block1.L_TITLE}&lt;/a&gt;
1542      <span class="comment">&lt;!-- ENDIF --&gt;</span>
1543  <span class="comment">&lt;!-- END l_block1 --&gt;</span>
1544  </pre></div>
1545  
1546  <p>Let us first concentrate on this part of the example:</p>
1547  
1548  <div class="codebox"><pre>
1549  <span class="comment">&lt;!-- BEGIN l_block1 --&gt;</span>
1550      <span class="comment">&lt;!-- IF l_block1.S_SELECTED --&gt;</span>
1551          markup
1552      <span class="comment">&lt;!-- ELSE --&gt;</span>
1553          &lt;a class=&quot;nav&quot; href=&quot;{l_block1.U_TITLE}&quot;&gt;{l_block1.L_TITLE}&lt;/a&gt;
1554      <span class="comment">&lt;!-- ENDIF --&gt;</span>
1555  <span class="comment">&lt;!-- END l_block1 --&gt;</span>
1556  </pre></div>
1557  
1558  <p>Here we open the loop l_block1 and do some things if the value S_SELECTED within the current loop iteration is true, else we write the blocks link and title. Here, you see <code>{l_block1.L_TITLE}</code> referenced - you remember that L_* variables get automatically assigned the corresponding language entry? This is true, but not within loops. The L_TITLE variable within the loop l_block1 is assigned within the code itself.</p>
1559  
1560  <p>Let's have a closer look at the markup:</p>
1561  
1562  <div class="codebox"><pre>
1563  <span class="comment">&lt;!-- BEGIN l_block1 --&gt;</span>
1564  .
1565  .
1566      <span class="comment">&lt;!-- IF S_PRIVMSGS --&gt;</span>
1567  
1568          <span class="comment">&lt;!-- BEGIN !folder --&gt;</span>
1569              <span class="comment">&lt;!-- IF folder.S_FIRST_ROW --&gt;</span>
1570                  &lt;ul class=&quot;nav&quot;&gt;
1571              <span class="comment">&lt;!-- ENDIF --&gt;</span>
1572  
1573              &lt;li&gt;&lt;a href=&quot;{folder.U_FOLDER}&quot;&gt;{folder.FOLDER_NAME}&lt;/a&gt;&lt;/li&gt;
1574  
1575              <span class="comment">&lt;!-- IF folder.S_LAST_ROW --&gt;</span>
1576                  &lt;/ul&gt;
1577              <span class="comment">&lt;!-- ENDIF --&gt;</span>
1578          <span class="comment">&lt;!-- END !folder --&gt;</span>
1579  
1580      <span class="comment">&lt;!-- ENDIF --&gt;</span>
1581  .
1582  .
1583  <span class="comment">&lt;!-- END l_block1 --&gt;</span>
1584  </pre></div>
1585  
1586  <p>The <code>&lt;!-- IF S_PRIVMSGS --&gt;</code> statement clearly checks a global variable and not one within the loop, since the loop is not given here. So, if S_PRIVMSGS is true we execute the shown markup. Now, you see the <code>&lt;!-- BEGIN !folder --&gt;</code> statement. The exclamation mark is responsible for instructing the template engine to iterate through the main loop folder. So, we are now within the loop folder - with <code>&lt;!-- BEGIN folder --&gt;</code> we would have been within the loop <code>l_block1.folder</code> automatically as is the case with l_block2:</p>
1587  
1588  <div class="codebox"><pre>
1589  <span class="comment">&lt;!-- BEGIN l_block1 --&gt;</span>
1590  .
1591  .
1592      &lt;ul class=&quot;nav&quot;&gt;
1593      <span class="comment">&lt;!-- BEGIN l_block2 --&gt;</span>
1594          &lt;li&gt;
1595              <span class="comment">&lt;!-- IF l_block1.l_block2.S_SELECTED --&gt;</span>
1596                  &lt;strong&gt;{l_block1.l_block2.L_TITLE}&lt;/strong&gt;
1597              <span class="comment">&lt;!-- ELSE --&gt;</span>
1598                  &lt;a href=&quot;{l_block1.l_block2.U_TITLE}&quot;&gt;{l_block1.l_block2.L_TITLE}&lt;/a&gt;
1599              <span class="comment">&lt;!-- ENDIF --&gt;</span>
1600          &lt;/li&gt;
1601      <span class="comment">&lt;!-- END l_block2 --&gt;</span>
1602      &lt;/ul&gt;
1603  .
1604  .
1605  <span class="comment">&lt;!-- END l_block1 --&gt;</span>
1606  </pre></div>
1607  
1608  <p>You see the difference? The loop l_block2 is a member of the loop l_block1 but the loop folder is a main loop.</p>
1609  
1610  <p>Now back to our folder loop:</p>
1611  
1612  <div class="codebox"><pre>
1613  <span class="comment">&lt;!-- IF folder.S_FIRST_ROW --&gt;</span>
1614      &lt;ul class=&quot;nav&quot;&gt;
1615  <span class="comment">&lt;!-- ENDIF --&gt;</span>
1616  
1617  &lt;li&gt;&lt;a href=&quot;{folder.U_FOLDER}&quot;&gt;{folder.FOLDER_NAME}&lt;/a&gt;&lt;/li&gt;
1618  
1619  <span class="comment">&lt;!-- IF folder.S_LAST_ROW --&gt;</span>
1620      &lt;/ul&gt;
1621  <span class="comment">&lt;!-- ENDIF --&gt;</span>
1622  </pre></div>
1623  
1624  <p>You may have wondered what the comparison to S_FIRST_ROW and S_LAST_ROW is about. If you haven't guessed already - it is checking for the first iteration of the loop with <code>S_FIRST_ROW</code> and the last iteration with <code>S_LAST_ROW</code>. This can come in handy quite often if you want to open or close design elements, like the above list. Let us imagine a folder loop build with three iterations, it would go this way:</p>
1625  
1626  <div class="codebox"><pre>
1627  &lt;ul class=&quot;nav&quot;&gt; <span class="comment">&lt;!-- written on first iteration --&gt;</span>
1628      &lt;li&gt;first element&lt;/li&gt; <span class="comment">&lt;!-- written on first iteration --&gt;</span>
1629      &lt;li&gt;second element&lt;/li&gt; <span class="comment">&lt;!-- written on second iteration --&gt;</span>
1630      &lt;li&gt;third element&lt;/li&gt; <span class="comment">&lt;!-- written on third iteration --&gt;</span>
1631  &lt;/ul&gt; <span class="comment">&lt;!-- written on third iteration --&gt;</span>
1632  </pre></div>
1633  
1634  <p>As you can see, all three elements are written down as well as the markup for the first iteration and the last one. Sometimes you want to omit writing the general markup - for example:</p>
1635  
1636  <div class="codebox"><pre>
1637  <span class="comment">&lt;!-- IF folder.S_FIRST_ROW --&gt;</span>
1638      &lt;ul class=&quot;nav&quot;&gt;
1639  <span class="comment">&lt;!-- ELSEIF folder.S_LAST_ROW --&gt;</span>
1640      &lt;/ul&gt;
1641  <span class="comment">&lt;!-- ELSE --&gt;</span>
1642      &lt;li&gt;&lt;a href=&quot;{folder.U_FOLDER}&quot;&gt;{folder.FOLDER_NAME}&lt;/a&gt;&lt;/li&gt;
1643  <span class="comment">&lt;!-- ENDIF --&gt;</span>
1644  </pre></div>
1645  
1646  <p>would result in the following markup:</p>
1647  
1648  <div class="codebox"><pre>
1649  &lt;ul class=&quot;nav&quot;&gt; <span class="comment">&lt;!-- written on first iteration --&gt;</span>
1650      &lt;li&gt;second element&lt;/li&gt; <span class="comment">&lt;!-- written on second iteration --&gt;</span>
1651  &lt;/ul&gt; <span class="comment">&lt;!-- written on third iteration --&gt;</span>
1652  </pre></div>
1653  
1654  <p>Just always remember that processing is taking place from top to bottom.</p>
1655  
1656      <h4>Forms</h4>
1657          <p>If a form is used for a non-trivial operation (i.e. more than a jumpbox), then it should include the <code>{S_FORM_TOKEN}</code> template variable.</p>
1658          <div class="codebox"><pre>
1659  &lt;form method=&quot;post&quot; id=&quot;mcp&quot; action=&quot;{U_POST_ACTION}&quot;&gt;
1660  
1661      &lt;fieldset class="submit-buttons"&gt;
1662          &lt;input type=&quot;reset&quot; value=&quot;{L_RESET}&quot; name=&quot;reset&quot; class=&quot;button2&quot; /&gt;&nbsp;
1663          &lt;input type=&quot;submit&quot; name=&quot;action[add_warning]&quot; value=&quot;{L_SUBMIT}&quot; class=&quot;button1&quot; /&gt;
1664          {S_FORM_TOKEN}
1665      &lt;/fieldset&gt;
1666  &lt;/form&gt;
1667          </pre></div><br />
1668  
1669      <a name="stylestree"></a><h3>4.ii. Styles Tree</h3>
1670          <p>When basing a new style on an existing one, it is not necessary to provide all the template files. By declaring the base style name in the <strong>parent</strong> field in the style configuration file, the style can be set to reuse template files from the parent style.</p>
1671  
1672          <p>The effect of doing so is that the template engine will use the template files in the new style where they exist, but fall back to files in the parent style otherwise.</p>
1673  
1674          <p>We strongly encourage the use of parent styles for styles based on the bundled styles, as it will ease the update procedure.</p>
1675  
1676          <div class="codebox"><pre>
1677  # General Information about this style
1678  name = Custom Style
1679  copyright = © phpBB Limited, 2007
1680  style_version = 3.1.0-b1
1681  phpbb_version = 3.1.0-b1
1682  
1683  # Defining a different template bitfield
1684  # template_bitfield = lNg=
1685  
1686  # Parent style
1687  # Set value to empty or to this style's name if this style does not have a parent style
1688  parent = prosilver
1689          </pre></div>
1690  
1691          <a name="template-events"></a><h3>4.iii. Template Events</h3>
1692          <p>Template events must follow this format: <code>&lt;!-- EVENT event_name --&gt;</code></p>
1693          <p>Using the above example, files named <code>event_name.html</code> located within extensions will be injected into the location of the event.</p>
1694  
1695          <h4>Template event naming guidelines:</h4>
1696          <ul>
1697              <li>An event name must be all lowercase, with each word separated by an underscore.</li>
1698              <li>An event name must briefly describe the location and purpose of the event.</li>
1699              <li>
1700                  An event name must end with one of the following suffixes:
1701                  <ul>
1702                      <li><code>_prepend</code> - This event adds an item to the beginning of a block of related items, or adds to the beginning of individual items in a block.</li>
1703                      <li><code>_append</code> - This event adds an item to the end of a block of related items, or adds to the end of individual items in a block.</li>
1704                      <li><code>_before</code> - This event adds content directly before the specified block</li>
1705                      <li><code>_after</code> - This event adds content directly after the specified block</li>
1706                  </ul>
1707              </li>
1708          </ul>
1709  
1710          <h4>Template event documentation</h4>
1711          <p>Events must be documented in <code>phpBB/docs/events.md</code> in alphabetical order based on the event name. The format is as follows:</p>
1712  
1713          <ul><li>An event found in only one template file:
1714          <div class="codebox"><pre>event_name
1715  ===
1716  * Location: styles/&lt;style_name&gt;/template/filename.html
1717  * Purpose: A brief description of what this event should be used for.
1718  This may span multiple lines.
1719  * Since: Version since when the event was added
1720  </pre></div></li>
1721          <li>An event found in multiple template files:
1722          <div class="codebox"><pre>event_name
1723  ===
1724  * Locations:
1725      + first/file/path.html
1726      + second/file/path.html
1727  * Purpose: Same as above.
1728  * Since: 3.1.0-b1
1729  </pre></div>
1730          <li>An event that is found multiple times in a file should have the number of instances in parenthesis next to the filename.
1731          <div class="codebox"><pre>event_name
1732  ===
1733  * Locations:
1734      + first/file/path.html (2)
1735      + second/file/path.html
1736  * Purpose: Same as above.
1737  * Since: 3.1.0-b1
1738  </pre></div></li>
1739          <li>An actual example event documentation:
1740          <div class="codebox"><pre>forumlist_body_last_post_title_prepend
1741  ====
1742  * Locations:
1743      + styles/prosilver/template/forumlist_body.html
1744      + styles/subsilver2/template/forumlist_body.html
1745  * Purpose: Add content before the post title of the latest post in a forum on the forum list.
1746  * Since: 3.1.0-a1
1747  </pre></div></ul><br />
1748  
1749          </div>
1750  
1751          <div class="back2top"><a href="#wrap" class="top">Back to Top</a></div>
1752  
1753          </div>
1754      </div>
1755  
1756      <hr />
1757  
1758  
1759  
1760  <a name="charsets"></a><h2>5. Character Sets and Encodings</h2>
1761  
1762      <div class="paragraph">
1763          <div class="inner">
1764  
1765          <div class="content">
1766  
1767  
1768  
1769  <h4>What are Unicode, UCS and UTF-8?</h4>
1770  <p>The <a href="http://en.wikipedia.org/wiki/Universal_Character_Set">Universal Character Set (UCS)</a> described in ISO/IEC 10646 consists of a large amount of characters. Each of them has a unique name and a code point which is an integer number. <a href="http://en.wikipedia.org/wiki/Unicode">Unicode</a> - which is an industry standard - complements the Universal Character Set with further information about the characters' properties and alternative character encodings. More information on Unicode can be found on the <a href="http://www.unicode.org/">Unicode Consortium's website</a>. One of the Unicode encodings is the <a href="http://en.wikipedia.org/wiki/UTF-8">8-bit Unicode Transformation Format (UTF-8)</a>. It encodes characters with up to four bytes aiming for maximum compatibility with the <a href="http://en.wikipedia.org/wiki/ASCII">American Standard Code for Information Interchange</a> which is a 7-bit encoding of a relatively small subset of the UCS.</p>
1771  
1772  <h4>phpBB's use of Unicode</h4>
1773  <p>Unfortunately PHP does not faciliate the use of Unicode prior to version 6. Most functions simply treat strings as sequences of bytes assuming that each character takes up exactly one byte. This behaviour still allows for storing UTF-8 encoded text in PHP strings but many operations on strings have unexpected results. To circumvent this problem we have created some alternative functions to PHP's native string operations which use code points instead of bytes. These functions can be found in <code>/includes/utf/utf_tools.php</code>. They are also covered in the <a href="http://area51.phpbb.com/docs/code/">phpBB3 Sourcecode Documentation</a>. A lot of native PHP functions still work with UTF-8 as long as you stick to certain restrictions. For example <code>explode</code> still works as long as the first and the last character of the delimiter string are ASCII characters.</p>
1774  
1775  <p>phpBB only uses the ASCII and the UTF-8 character encodings. Still all Strings are UTF-8 encoded because ASCII is a subset of UTF-8. The only exceptions to this rule are code sections which deal with external systems which use other encodings and character sets. Such external data should be converted to UTF-8 using the <code>utf8_recode()</code> function supplied with phpBB. It supports a variety of other character sets and encodings, a full list can be found below.</p>
1776  
1777  <p>With <code>$request->variable()</code> you can either allow all UCS characters in user input or restrict user input to ASCII characters. This feature is controlled by the method's third parameter called <code>$multibyte</code>. You should allow multibyte characters in posts, PMs, topic titles, forum names, etc. but it's not necessary for internal uses like a <code>$mode</code> variable which should only hold a predefined list of ASCII strings anyway.</p>
1778  
1779  <div class="codebox"><pre>
1780  // an input string containing a multibyte character
1781  $_REQUEST['multibyte_string'] = 'K&#228;se';
1782  
1783  // print request variable as a UTF-8 string allowing multibyte characters
1784  echo $request->variable('multibyte_string', '', true);
1785  // print request variable as ASCII string
1786  echo $request->variable('multibyte_string', '');
1787  </pre></div>
1788  
1789  <p>This code snippet will generate the following output:</p>
1790  
1791  <div class="codebox"><pre>
1792  K&#228;se
1793  K??se
1794  </pre></div>
1795  
1796  <h4>Case Folding</h4>
1797  
1798  <p>Case insensitive comparison of strings is no longer possible with <code>strtolower</code> or <code>strtoupper</code> as some characters have multiple lower case or multiple upper case forms depending on their position in a word. The <code>utf8_strtolower</code> and the <code>utf8_strtoupper</code> functions suffer from the same problem so they can only be used to display upper/lower case versions of a string but they cannot be used for case insensitive comparisons either. So instead you should use case folding which gives you a case insensitive version of the string which can be used for case insensitive comparisons. An NFC normalized string can be case folded using <code>utf8_case_fold_nfc()</code>.</p>
1799  
1800  <p class="bad">// Bad - The strings might be the same even if strtolower differs</p>
1801  
1802  <div class="codebox"><pre>
1803  if (strtolower($string1) == strtolower($string2))
1804  {
1805      echo '$string1 and $string2 are equal or differ in case';
1806  }
1807  </pre></div>
1808  
1809  <p class="good">// Good - Case folding is really case insensitive</p>
1810  
1811  <div class="codebox"><pre>
1812  if (utf8_case_fold_nfc($string1) == utf8_case_fold_nfc($string2))
1813  {
1814      echo '$string1 and $string2 are equal or differ in case';
1815  }
1816  </pre></div>
1817  
1818  <h4>Confusables Detection</h4>
1819  
1820  <p>phpBB offers a special method <code>utf8_clean_string</code> which can be used to make sure string identifiers are unique. This method uses Normalization Form Compatibility Composition (NFKC) instead of NFC and replaces similarly looking characters with a particular representative of the equivalence class. This method is currently used for usernames and group names to avoid confusion with similarly looking names.</p>
1821  
1822          </div>
1823  
1824          <div class="back2top"><a href="#wrap" class="top">Back to Top</a></div>
1825  
1826          </div>
1827      </div>
1828  
1829      <hr />
1830  
1831  <a name="translation"></a><h2>6. Translation (<abbr title="Internationalisation">i18n</abbr>/<abbr title="Localisation">L10n</abbr>) Guidelines</h2>
1832  
1833      <div class="paragraph">
1834          <div class="inner">
1835  
1836          <div class="content">
1837  
1838      <a name="standardisation"></a><h3>6.i. Standardisation</h3>
1839  
1840      <h4>Reason:</h4>
1841  
1842      <p>phpBB is one of the most translated open-source projects, with the current stable version being available in over 60 localisations. Whilst the ad hoc approach to the naming of language packs has worked, for phpBB3 and beyond we hope to make this process saner which will allow for better interoperation with current and future web browsers.</p>
1843  
1844      <h4>Encoding:</h4>
1845  
1846      <p>With phpBB3, the output encoding for the forum in now UTF-8, a Universal Character Encoding by the Unicode Consortium that is by design a superset to US-ASCII and ISO-8859-1. By using one character set which simultaenously supports all scripts which previously would have required different encodings (eg: ISO-8859-1 to ISO-8859-15 (Latin, Greek, Cyrillic, Thai, Hebrew, Arabic); GB2312 (Simplified Chinese); Big5 (Traditional Chinese), EUC-JP (Japanese), EUC-KR (Korean), VISCII (Vietnamese); et cetera), we remove the need to convert between encodings and improves the accessibility of multilingual forums.</p>
1847  
1848      <p>The impact is that the language files for phpBB must now also be encoded as UTF-8, with a caveat that the files must <strong>not contain</strong> a <abbr title="Byte-Order-Mark">BOM</abbr> for compatibility reasons with non-Unicode aware versions of PHP. For those with forums using the Latin character set (ie: most European languages), this change is transparent since UTF-8 is superset to US-ASCII and ISO-8859-1.</p>
1849  
1850      <h4>Language Tag:</h4>
1851  
1852      <p>The <abbr title="Internet Engineering Task Force">IETF</abbr> recently published <a href="http://tools.ietf.org/html/rfc4646">RFC 4646</a> for tags used to identify languages, which in combination with <a href="http://tools.ietf.org/html/rfc4647">RFC 4647</a> obseletes the older <a href="http://tools.ietf.org/html/rfc3066">RFC 3006</a> and older-still <a href="http://tools.ietf.org/html/rfc1766">RFC 1766</a>. <a href="http://tools.ietf.org/html/rfc4646">RFC 4646</a> uses <a href="http://www.loc.gov/standards/iso639-2/php/English_list.php">ISO 639-1/ISO 639-2</a>, <a href="http://www.iso.ch/iso/en/prods-services/iso3166ma/02iso-3166-code-lists/list-en1.html">ISO 3166-1 alpha-2</a>, <a href="http://www.unicode.org/iso15924/iso15924-codes.html">ISO 15924</a> and <a href="http://unstats.un.org/unsd/methods/m49/m49.htm">UN M.49</a> to define a language tag. Each complete tag is composed of subtags which are not case sensitive and can also be empty.</p>
1853  
1854      <p>Ordering of the subtags in the case that they are all non-empty is: <code>language</code>-<code>script</code>-<code>region</code>-<code>variant</code>-<code>extension</code>-<code>privateuse</code>. Should any subtag be empty, its corresponding hyphen would also be ommited. Thus, the language tag for English will be <code>en</code> <strong>and not</strong> <code>en-----</code>.</p>
1855  
1856      <p>Most language tags consist of a two- or three-letter language subtag (from <a href="http://www.loc.gov/standards/iso639-2/php/English_list.php">ISO 639-1/ISO 639-2</a>). Sometimes, this is followed by a two-letter or three-digit region subtag (from <a href="http://www.iso.ch/iso/en/prods-services/iso3166ma/02iso-3166-code-lists/list-en1.html">ISO 3166-1 alpha-2</a> or <a href="http://unstats.un.org/unsd/methods/m49/m49.htm">UN M.49</a>). Some examples are:</p>
1857  
1858      <table>
1859      <caption>Examples of various possible language tags as described by RFC 4646 and RFC 4647</caption>
1860      <thead>
1861      <tr>
1862          <th scope="col">Language tag</th>
1863          <th scope="col">Description</th>
1864          <th scope="col">Component subtags</th>
1865      </tr>
1866      </thead>
1867      <tbody>
1868      <tr>
1869          <td><code>en</code></td>
1870          <td>English</td>
1871          <td><code>language</code></td>
1872      </tr>
1873      <tr>
1874          <td><code>mas</code></td>
1875          <td>Masai</td>
1876          <td><code>language</code></td>
1877      </tr>
1878      <tr>
1879          <td><code>fr-CA</code></td>
1880          <td>French as used in Canada</td>
1881          <td><code>language</code>+<code>region</code></td>
1882      </tr>
1883      <tr>
1884          <td><code>en-833</code></td>
1885          <td>English as used in the Isle of Man</td>
1886          <td><code>language</code>+<code>region</code></td>
1887      </tr>
1888      <tr>
1889          <td><code>zh-Hans</code></td>
1890          <td>Chinese written with Simplified script</td>
1891          <td><code>language</code>+<code>script</code></td>
1892      </tr>
1893      <tr>
1894          <td><code>zh-Hant-HK</code></td>
1895          <td>Chinese written with Traditional script as used in Hong Kong</td>
1896          <td><code>language</code>+<code>script</code>+<code>region</code></td>
1897      </tr>
1898      <tr>
1899          <td><code>de-AT-1996</code></td>
1900          <td>German as used in Austria with 1996 orthography</td>
1901          <td><code>language</code>+<code>region</code>+<code>variant</code></td>
1902      </tr>
1903      </tbody>
1904      </table>
1905  
1906      <p>The ultimate aim of a language tag is to convey the needed <strong>useful distingushing information</strong>, whilst keeping it as <strong>short as possible</strong>. So for example, use <code>en</code>, <code>fr</code> and <code>ja</code> as opposed to <code>en-GB</code>, <code>fr-FR</code> and <code>ja-JP</code>, since we know English, French and Japanese are the native language of Great Britain, France and Japan respectively.</p>
1907  
1908      <p>Next is the <a href="http://www.unicode.org/iso15924/iso15924-codes.html">ISO 15924</a> language script code and when one should or shouldn't use it. For example, whilst <code>en-Latn</code> is syntaxically correct for describing English written with Latin script, real world English writing is <strong>more-or-less exclusively in the Latin script</strong>. For such languages like English that are written in a single script, the <a href="http://www.iana.org/assignments/language-subtag-registry"><abbr title="Internet Assigned Numbers Authority">IANA</abbr> Language Subtag Registry</a> has a "Suppress-Script" field meaning the script code <strong>should be ommitted</strong> unless a specific language tag requires a specific script code. Some languages are <strong>written in more than one script</strong> and in such cases, the script code <strong>is encouraged</strong> since an end-user may be able to read their language in one script, but not the other. Some examples are:</p>
1909  
1910      <table>
1911      <caption>Examples of using a language subtag in combination with a script subtag</caption>
1912      <thead>
1913      <tr>
1914          <th scope="col">Language tag</th>
1915          <th scope="col">Description</th>
1916          <th scope="col">Component subtags</th>
1917      </tr>
1918      </thead>
1919      <tbody>
1920      <tr>
1921          <td><code>en-Brai</code></td>
1922          <td>English written in Braille script</td>
1923          <td><code>language</code>+<code>script</code></td>
1924      </tr>
1925      <tr>
1926          <td><code>en-Dsrt</code></td>
1927          <td>English written in Deseret (Mormon) script</td>
1928          <td><code>language</code>+<code>script</code></td>
1929      </tr>
1930      <tr>
1931          <td><code>sr-Latn</code></td>
1932          <td>Serbian written in Latin script</td>
1933          <td><code>language</code>+<code>script</code></td>
1934      </tr>
1935      <tr>
1936          <td><code>sr-Cyrl</code></td>
1937          <td>Serbian written in Cyrillic script</td>
1938          <td><code>language</code>+<code>script</code></td>
1939      </tr>
1940      <tr>
1941          <td><code>mn-Mong</code></td>
1942          <td>Mongolian written in Mongolian script</td>
1943          <td><code>language</code>+<code>script</code></td>
1944      </tr>
1945      <tr>
1946          <td><code>mn-Cyrl</code></td>
1947          <td>Mongolian written in Cyrillic script</td>
1948          <td><code>language</code>+<code>script</code></td>
1949      </tr>
1950      <tr>
1951          <td><code>mn-Phag</code></td>
1952          <td>Mongolian written in Phags-pa script</td>
1953          <td><code>language</code>+<code>script</code></td>
1954      </tr>
1955      <tr>
1956          <td><code>az-Cyrl-AZ</code></td>
1957          <td>Azerbaijani written in Cyrillic script as used in Azerbaijan</td>
1958          <td><code>language</code>+<code>script</code>+<code>region</code></td>
1959      </tr>
1960      <tr>
1961          <td><code>az-Latn-AZ</code></td>
1962          <td>Azerbaijani written in Latin script as used in Azerbaijan</td>
1963          <td><code>language</code>+<code>script</code>+<code>region</code></td>
1964      </tr>
1965      <tr>
1966          <td><code>az-Arab-IR</code></td>
1967          <td>Azerbaijani written in Arabic script as used in Iran</td>
1968          <td><code>language</code>+<code>script</code>+<code>region</code></td>
1969      </tr>
1970      </tbody>
1971      </table>
1972  
1973      <p>Usage of the three-digit <a href="http://unstats.un.org/unsd/methods/m49/m49.htm">UN M.49</a> code over the two-letter <a href="http://www.iso.ch/iso/en/prods-services/iso3166ma/02iso-3166-code-lists/list-en1.html">ISO 3166-1 alpha-2</a> code should hapen if a macro-geographical entity is required and/or the <a href="http://www.iso.ch/iso/en/prods-services/iso3166ma/02iso-3166-code-lists/list-en1.html">ISO 3166-1 alpha-2</a> is ambiguous.</p>
1974  
1975      <p>Examples of English using marco-geographical regions:</p>
1976  
1977      <table>
1978      <caption>Coding for English using macro-geographical regions (examples for English of ISO 3166-1 alpha-2 vs. UN M.49 code)</caption>
1979      <thead>
1980      <tr>
1981          <th scope="col">ISO 639-1/ISO 639-2 + ISO 3166-1 alpha-2</th>
1982          <th scope="col" colspan="2">ISO 639-1/ISO 639-2 + UN M.49 (Example macro regions)</th>
1983      </tr>
1984      </thead>
1985      <tbody>
1986      <tr>
1987          <td><dl><dt><code>en-AU</code></dt><dd>English as used in <strong>Australia</strong></dd></dl></td>
1988          <td rowspan="2"><dl><dt><code>en-053</code></dt><dd>English as used in <strong>Australia &amp; New Zealand</strong></dd></dl></td>
1989          <td rowspan="3"><dl><dt><code>en-009</code></dt><dd>English as used in <strong>Oceania</strong></dd></dl></td>
1990      </tr>
1991      <tr>
1992          <td><dl><dt><code>en-NZ</code></dt><dd>English as used in <strong>New Zealand</strong></dd></dl></td>
1993      </tr>
1994      <tr>
1995          <td><dl><dt><code>en-FJ</code></dt><dd>English as used in <strong>Fiji</strong></dd></dl></td>
1996          <td><dl><dt><code>en-054 </code></dt><dd>English as used in <strong>Melanesia</strong></dd></dl></td>
1997      </tr>
1998      </tbody>
1999      </table>
2000  
2001      <p>Examples of Spanish using marco-geographical regions:</p>
2002  
2003      <table>
2004      <caption>Coding for Spanish macro-geographical regions (examples for Spanish of ISO 3166-1 alpha-2 vs. UN M.49 code)</caption>
2005      <thead>
2006      <tr>
2007          <th scope="col">ISO 639-1/ISO 639-2 + ISO 3166-1 alpha-2</th>
2008          <th scope="col" colspan="2">ISO 639-1/ISO 639-2 + UN M.49 (Example macro regions)</th>
2009      </tr>
2010      </thead>
2011      <tbody>
2012      <tr>
2013          <td><dl><dt><code>es-PR</code></dt><dd>Spanish as used in <strong>Puerto Rico</strong></dd></dl></td>
2014          <td rowspan="3"><dl><dt><code>es-419</code></dt><dd>Spanish as used in <strong>Latin America &amp; the Caribbean</strong></dd></dl></td>
2015          <td rowspan="4"><dl><dt><code>es-019</code></dt><dd>Spanish as used in <strong>the Americas</strong></dd></dl></td>
2016      </tr>
2017      <tr>
2018          <td><dl><dt><code>es-HN</code></dt><dd>Spanish as used in <strong>Honduras</strong></dd></dl></td>
2019      </tr>
2020      <tr>
2021          <td><dl><dt><code>es-AR</code></dt><dd>Spanish as used in <strong>Argentina</strong></dd></dl></td>
2022      </tr>
2023      <tr>
2024          <td><dl><dt><code>es-US</code></dt><dd>Spanish as used in <strong>United States of America</strong></dd></dl></td>
2025          <td><dl><dt><code>es-021</code></dt><dd>Spanish as used in <strong>North America</strong></dd></dl></td>
2026      </tr>
2027      </tbody>
2028      </table>
2029  
2030      <p>Example of where the <a href="http://www.iso.ch/iso/en/prods-services/iso3166ma/02iso-3166-code-lists/list-en1.html">ISO 3166-1 alpha-2</a> is ambiguous and why <a href="http://unstats.un.org/unsd/methods/m49/m49.htm">UN M.49</a> might be preferred:</p>
2031  
2032      <table>
2033      <caption>Coding for ambiguous ISO 3166-1 alpha-2 regions</caption>
2034      <thead>
2035      <tr>
2036          <th scope="col" colspan="2"><code>CS</code> assignment pre-1994</th>
2037          <th scope="col" colspan="2"><code>CS</code> assignment post-1994</th>
2038      </tr>
2039      </thead>
2040      <tbody>
2041      <tr>
2042          <td colspan="2">
2043          <dl>
2044          <dt><code>CS</code></dt><dd><strong>Czechoslovakia</strong> (ISO 3166-1)</dd>
2045          <dt><code>200</code></dt><dd><strong>Czechoslovakia</strong> (UN M.49)</dd>
2046          </dl>
2047          </td>
2048          <td colspan="2">
2049          <dl>
2050          <dt><code>CS</code></dt><dd><strong>Serbian &amp; Montenegro</strong> (ISO 3166-1)</dd>
2051          <dt><code>891</code></dt><dd><strong>Serbian &amp; Montenegro</strong> (UN M.49)</dd>
2052          </dl>
2053          </td>
2054      </tr>
2055      <tr>
2056          <td>
2057          <dl>
2058          <dt><code>CZ</code></dt><dd><strong>Czech Republic</strong> (ISO 3166-1)</dd>
2059          <dt><code>203</code></dt><dd><strong>Czech Republic</strong> (UN M.49)</dd>
2060          </dl>
2061          </td>
2062          <td>
2063          <dl>
2064          <dt><code>SK</code></dt><dd><strong>Slovakia</strong> (ISO 3166-1)</dd>
2065          <dt><code>703</code></dt><dd><strong>Slovakia</strong> (UN M.49)</dd>
2066          </dl>
2067          </td>
2068          <td>
2069          <dl>
2070          <dt><code>RS</code></dt><dd><strong>Serbia</strong> (ISO 3166-1)</dd>
2071          <dt><code>688</code></dt><dd><strong>Serbia</strong> (UN M.49)</dd>
2072          </dl>
2073          </td>
2074          <td>
2075          <dl>
2076          <dt><code>ME</code></dt><dd><strong>Montenegro</strong> (ISO 3166-1)</dd>
2077          <dt><code>499</code></dt><dd><strong>Montenegro</strong> (UN M.49)</dd>
2078          </dl>
2079          </td>
2080      </tr>
2081      </tbody>
2082      </table>
2083  
2084      <h4>Macro-languages &amp; Topolects:</h4>
2085  
2086      <p><a href="http://tools.ietf.org/html/rfc4646">RFC 4646</a> anticipates features which shall be available in (currently draft) <a href="http://www.sil.org/iso639-3/">ISO 639-3</a> which aims to provide as complete enumeration of languages as possible, including living, extinct, ancient and constructed languages, whether majour, minor or unwritten. A new feature of <a href="http://www.sil.org/iso639-3/">ISO 639-3</a> compared to the previous two revisions is the concept of <a href="http://www.sil.org/iso639-3/macrolanguages.asp">macrolanguages</a> where Arabic and Chinese are two such examples. In such cases, their respective codes of <code>ar</code> and <code>zh</code> is very vague as to which dialect/topolect is used or perhaps some terse classical variant which may be difficult for all but very educated users. For such macrolanguages, it is recommended that the sub-language tag is used as a suffix to the macrolanguage tag, eg:</p>
2087  
2088      <table>
2089      <caption>Macrolanguage subtag + sub-language subtag examples</caption>
2090      <thead>
2091      <tr>
2092          <th scope="col">Language tag</th>
2093          <th scope="col">Description</th>
2094          <th scope="col">Component subtags</th>
2095      </tr>
2096      </thead>
2097      <tbody>
2098      <tr>
2099          <td><code>zh-cmn</code></td>
2100          <td>Mandarin (Putonghau/Guoyu) Chinese</td>
2101          <td><code>macrolanguage</code>+<code>sublanguage</code></td>
2102      </tr>
2103      <tr>
2104          <td><code>zh-yue</code></td>
2105          <td>Yue (Cantonese) Chinese</td>
2106          <td><code>macrolanguage</code>+<code>sublanguage</code></td>
2107      </tr>
2108      <tr>
2109          <td><code>zh-cmn-Hans</code></td>
2110          <td>Mandarin (Putonghau/Guoyu) Chinese written in Simplified script</td>
2111          <td><code>macrolanguage</code>+<code>sublanguage</code>+<code>script</code></td>
2112      </tr>
2113      <tr>
2114          <td><code>zh-cmn-Hant</code></td>
2115          <td>Mandarin (Putonghau/Guoyu) Chinese written in Traditional script</td>
2116          <td><code>macrolanguage</code>+<code>sublanguage</code>+<code>script</code></td>
2117      </tr>
2118      <tr>
2119          <td><code>zh-nan-Latn-TW</code></td>
2120          <td>Minnan (Hoklo) Chinese written in Latin script (POJ Romanisation) as used in Taiwan</td>
2121          <td><code>macrolanguage</code>+<code>sublanguage</code>+<code>script</code>+<code>region</code></td>
2122      </tr>
2123      </tbody>
2124      </table>
2125  
2126      <a name="otherconsiderations"></a><h3>6.ii. Other considerations</h3>
2127  
2128      <h4>Normalisation of language tags for phpBB:</h4>
2129  
2130      <p>For phpBB, the language tags are <strong>not</strong> used in their raw form and instead converted to all lower-case and have the hyphen <code>-</code> replaced with an underscore <code>_</code> where appropriate, with some examples below:</p>
2131  
2132      <table>
2133      <caption>Language tag normalisation examples</caption>
2134      <thead>
2135      <tr>
2136          <th scope="col">Raw language tag</th>
2137          <th scope="col">Description</th>
2138          <th scope="col">Value of <code>USER_LANG</code><br />in <code>./common.php</code></th>
2139          <th scope="col">Language pack directory<br />name in <code>/language/</code></th>
2140      </tr>
2141      </thead>
2142      <tbody>
2143      <tr>
2144          <td><code>en</code></td>
2145          <td>British English</td>
2146          <td><code>en</code></td>
2147          <td><code>en</code></td>
2148      </tr>
2149      <tr>
2150          <td><code>de-AT</code></td>
2151          <td>German as used in Austria</td>
2152          <td><code>de-at</code></td>
2153          <td><code>de_at</code></td>
2154      </tr>
2155      <tr>
2156          <td><code>es-419</code></td>
2157          <td>Spanish as used in Latin America &amp; Caribbean</td>
2158          <td><code>en-419</code></td>
2159          <td><code>en_419</code></td>
2160      </tr>
2161      <tr>
2162          <td><code>zh-yue-Hant-HK</code></td>
2163          <td>Cantonese written in Traditional script as used in Hong Kong</td>
2164          <td><code>zh-yue-hant-hk</code></td>
2165          <td><code>zh_yue_hant_hk</code></td>
2166      </tr>
2167      </tbody>
2168      </table>
2169  
2170      <h4>How to use <code>iso.txt</code>:</h4>
2171  
2172      <p>The <code>iso.txt</code> file is a small UTF-8 encoded plain-text file which consists of three lines:</p>
2173  
2174      <ol>
2175          <li><code>Language's English name</code></li>
2176          <li><code>Language's local name</code></li>
2177          <li><code>Authors information</code></li>
2178      </ol>
2179  
2180      <p><code>iso.txt</code> is automatically generated by the language pack submission system on phpBB.com. You don't have to create this file yourself if you plan on releasing your language pack on phpBB.com, but do keep in mind that phpBB itself does require this file to be present.</p>
2181  
2182      <p>Because language tags themselves are meant to be machine read, they can be rather obtuse to humans and why descriptive strings as provided by <code>iso.txt</code> are needed. Whilst <code>en-US</code> could be fairly easily deduced to be "English as used in the United States", <code>de-CH</code> is more difficult less one happens to know that <code>de</code> is from "<span lang="de">Deutsch</span>", German for "German" and <code>CH</code> is the abbreviation of the official Latin name for Switzerland, "<span lang="la">Confoederatio Helvetica</span>".</p>
2183  
2184      <p>For the English language description, the language name is always first and any additional attributes required to describe the subtags within the language code are then listed in order separated with commas and enclosed within parentheses, eg:</p>
2185  
2186      <table>
2187      <caption>English language description examples for iso.txt</caption>
2188      <thead>
2189      <tr>
2190          <th scope="col">Raw language tag</th>
2191          <th scope="col">English description within <code>iso.txt</code></th>
2192      </tr>
2193      </thead>
2194      <tbody>
2195      <tr>
2196          <td><code>en</code></td>
2197          <td>British English</td>
2198      </tr>
2199      <tr>
2200          <td><code>en-US</code></td>
2201          <td>English (United States)</td>
2202      </tr>
2203      <tr>
2204          <td><code>en-053</code></td>
2205          <td>English (Australia &amp; New Zealand)</td>
2206      </tr>
2207      <tr>
2208          <td><code>de</code></td>
2209          <td>German</td>
2210      </tr>
2211      <tr>
2212          <td><code>de-CH-1996</code></td>
2213          <td>German (Switzerland, 1996 orthography)</td>
2214      </tr>
2215      <tr>
2216          <td><code>gws-1996</code></td>
2217          <td>Swiss German (1996 orthography)</td>
2218      </tr>
2219      <tr>
2220          <td><code>zh-cmn-Hans-CN</code></td>
2221          <td>Mandarin Chinese (Simplified, Mainland China)</td>
2222      </tr>
2223      <tr>
2224          <td><code>zh-yue-Hant-HK</code></td>
2225          <td>Cantonese Chinese (Traditional, Hong Kong)</td>
2226      </tr>
2227      </tbody>
2228      </table>
2229  
2230      <p>For the localised language description, just translate the English version though use whatever appropriate punctuation typical for your own locale, assuming the language uses punctuation at all.</p>
2231  
2232      <h4>Unicode bi-directional considerations:</h4>
2233  
2234      <p>Because phpBB is now UTF-8, all translators must take into account that certain strings may be shown when the directionality of the document is either opposite to normal or is ambiguous.</p>
2235  
2236      <p>The various Unicode control characters for bi-directional text and their HTML enquivalents where appropriate are as follows:</p>
2237  
2238      <table>
2239      <caption>Unicode bidirectional control characters &amp; HTML elements/entities</caption>
2240      <thead>
2241      <tr>
2242          <th scope="col">Unicode character<br />abbreviation</th>
2243          <th scope="col">Unicode<br />code-point</th>
2244          <th scope="col">Unicode character<br />name</th>
2245          <th scope="col">Equivalent HTML<br />markup/entity</th>
2246          <th scope="col">Raw character<br />(enclosed between '')</th>
2247      </tr>
2248      </thead>
2249      <tbody>
2250      <tr>
2251          <td><code>LRM</code></td>
2252          <td><code>U+200E</code></td>
2253          <td>Left-to-Right Mark</td>
2254          <td><code>&amp;lrm;</code></td>
2255          <td>'&#x200E;'</td>
2256      </tr>
2257      <tr>
2258          <td><code>RLM</code></td>
2259          <td><code>U+200F</code></td>
2260          <td>Right-to-Left Mark</td>
2261          <td><code>&amp;rlm;</code></td>
2262          <td>'&#x200F;'</td>
2263      </tr>
2264      <tr>
2265          <td><code>LRE</code></td>
2266          <td><code>U+202A</code></td>
2267          <td>Left-to-Right Embedding</td>
2268          <td><code>dir=&quot;ltr&quot;</code></td>
2269          <td>'&#x202A;'</td>
2270      </tr>
2271      <tr>
2272          <td><code>RLE</code></td>
2273          <td><code>U+202B</code></td>
2274          <td>Right-to-Left Embedding</td>
2275          <td><code>dir=&quot;rtl&quot;</code></td>
2276          <td>'&#x202B;'</td>
2277      </tr>
2278      <tr>
2279          <td><code>PDF</code></td>
2280          <td><code>U+202C</code></td>
2281          <td>Pop Directional Formatting</td>
2282          <td><code>&lt;/bdo&gt;</code></td>
2283          <td>'&#x202C;'</td>
2284      </tr>
2285      <tr>
2286          <td><code>LRO</code></td>
2287          <td><code>U+202D</code></td>
2288          <td>Left-to-Right Override</td>
2289          <td><code>&lt;bdo dir=&quot;ltr&quot;&gt;</code></td>
2290          <td>'&#x202D;'</td>
2291      </tr>
2292      <tr>
2293          <td><code>RLO</code></td>
2294          <td><code>U+202E</code></td>
2295          <td>Right-to-Left Override</td>
2296          <td><code>&lt;bdo dir=&quot;rtl&quot;&gt;</code></td>
2297          <td>'&#x202E;'</td>
2298      </tr>
2299      </tbody>
2300      </table>
2301  
2302      <p>For <code>iso.txt</code>, the directionality of the text can be explicitly set using special Unicode characters via any of the three methods provided by left-to-right/right-to-left markers/embeds/overrides, as without them, the ordering of characters will be incorrect, eg:</p>
2303  
2304      <table>
2305      <caption>Unicode bidirectional control characters iso.txt</caption>
2306      <thead>
2307      <tr>
2308          <th scope="col">Directionality</th>
2309          <th scope="col">Raw character view</th>
2310          <th scope="col">Display of localised<br />description in <code>iso.txt</code></th>
2311          <th scope="col">Ordering</th>
2312      </tr>
2313      </thead>
2314      <tbody>
2315      <tr>
2316          <td><code>dir=&quot;ltr&quot;</code></td>
2317          <td>English (Australia &amp; New Zealand)</td>
2318          <td dir="ltr">English (Australia &amp; New Zealand)</td>
2319          <td class="good">Correct</td>
2320      </tr>
2321      <tr>
2322          <td><code>dir=&quot;rtl&quot;</code></td>
2323          <td>English (Australia &amp; New Zealand)</td>
2324          <td dir="rtl">English (Australia &amp; New Zealand)</td>
2325          <td class="bad">Incorrect</td>
2326      </tr>
2327      <tr>
2328          <td><code>dir=&quot;rtl&quot;</code> with <code>LRM</code></td>
2329          <td>English (Australia &amp; New Zealand)<code>U+200E</code></td>
2330          <td dir="rtl">English (Australia &amp; New Zealand)&#x200E;</td>
2331          <td class="good">Correct</td>
2332      </tr>
2333      <tr>
2334          <td><code>dir=&quot;rtl&quot;</code> with <code>LRE</code> &amp; <code>PDF</code></td>
2335          <td><code>U+202A</code>English (Australia &amp; New Zealand)<code>U+202C</code></td>
2336          <td dir="rtl">&#x202A;English (Australia &amp; New Zealand)&#x202C;</td>
2337          <td class="good">Correct</td>
2338      </tr>
2339      <tr>
2340          <td><code>dir=&quot;rtl&quot;</code> with <code>LRO</code> &amp; <code>PDF</code></td>
2341          <td><code>U+202D</code>English (Australia &amp; New Zealand)<code>U+202C</code></td>
2342          <td dir="rtl">&#x202D;English (Australia &amp; New Zealand)&#x202C;</td>
2343          <td class="good">Correct</td>
2344      </tr>
2345      </tbody>
2346      </table>
2347  
2348      <p>In choosing which of the three methods to use, in the majority of cases, the <code>LRM</code> or <code>RLM</code> to put a &quot;strong&quot; character to fully enclose an ambiguous punctuation character and thus make it inherit the correct directionality is sufficient.</p>
2349      <p>Within some cases, there may be mixed scripts of a left-to-right and right-to-left direction, so using <code>LRE</code> &amp; <code>RLE</code> with <code>PDF</code> may be more appropriate. Lastly, in very rare instances where directionality must be forced, then use <code>LRO</code> &amp; <code>RLO</code> with <code>PDF</code>.</p>
2350      <p>For further information on authoring techniques of bi-directional text, please see the W3C tutorial on <a href="http://www.w3.org/International/tutorials/bidi-xhtml/">authoring techniques for XHTML pages with bi-directional text</a>.</p>
2351  
2352      <a name="placeholders"></a><h3>6.iii. Working with placeholders</h3>
2353  
2354      <p>As phpBB is translated into languages with different ordering rules to that of English, it is possible to show specific values in any order deemed appropriate. Take for example the extremely simple &quot;Page <em>X</em> of <em>Y</em>&quot;, whilst in English this could just be coded as:</p>
2355  
2356      <div class="codebox"><pre>
2357      ...
2358  'PAGE_OF'    =&gt;    'Page %s of %s',
2359          /* Just grabbing the replacements as they
2360          come and hope they are in the right order */
2361      ...</pre>
2362      </div>
2363  
2364      <p>&hellip; a clearer way to show explicit replacement ordering is to do:</p>
2365  
2366      <div class="codebox"><pre>
2367      ...
2368  'PAGE_OF'    =&gt;    'Page %1$s of %2$s',
2369          /* Explicit ordering of the replacements,
2370          even if they are the same order as English */
2371      ...</pre>
2372      </div>
2373  
2374      <p>Why bother at all? Because some languages, the string transliterated back to English might read something like:</p>
2375  
2376      <div class="codebox"><pre>
2377      ...
2378  'PAGE_OF'    =&gt;    'Total of %2$s pages, currently on page %1$s',
2379          /* Explicit ordering of the replacements,
2380          reversed compared to English as the total comes first */
2381      ...</pre>
2382      </div>
2383  
2384      <a name="usingplurals"></a><h3>6.iv. Using plurals</h3>
2385  
2386      <p>
2387          The english language is very simple when it comes to plurals.<br />
2388          You have <code>0 elephants</code>, <code>1 elephant</code>, or <code>2+ elephants</code>. So basically you have 2 different forms: one singular and one plural.<br />
2389          But for some other languages this is quite more difficult. Let's take the Bosnian language as another example:<br />
2390          You have <code>[1/21/31] slon</code>, <code>[2/3/4] slona</code>, <code>[0/5/6] slonova</code> and <code>[7/8/9/11] ...</code> and some more difficult rules.
2391      </p>
2392  
2393      <p>The <a href="https://wiki.phpbb.com/Plural_Rules">plural system</a> takes care of this and can be used as follows:</p>
2394  
2395      <p>The PHP code will basically look like this:</p>
2396  
2397      <div class="codebox"><pre>
2398      ...
2399      $user->lang('NUMBER_OF_ELEPHANTS', $number_of_elephants);
2400      ...</pre>
2401      </div>
2402  
2403      <p>And the English translation would be:</p>
2404  
2405      <div class="codebox"><pre>
2406      ...
2407      'NUMBER_OF_ELEPHANTS'    => array(
2408          0    => 'You have no elephants', // Optional special case for 0
2409          1    => 'You have 1 elephant', // Singular
2410          2    => 'You have %d elephants', // Plural
2411      ),
2412      ...</pre>
2413      </div>
2414  
2415      <p>While the Bosnian translation can have more cases:</p>
2416  
2417      <div class="codebox"><pre>
2418      ...
2419      'NUMBER_OF_ELEPHANTS'    => array(
2420          0    => 'You have no slonova', // Optional special case for 0
2421          1    => 'You have %d slon', // Used for 1, 21, 31, ..
2422          2    => 'You have %d slona', // Used for 5, 6,
2423          3    => ...
2424      ),
2425      ...</pre>
2426      </div>
2427  
2428      <p><strong>NOTE:</strong> It is okay to use plurals for an unknown number compared to a single item, when the number is not known and displayed:</p>
2429      <div class="codebox"><pre>
2430      ...
2431      'MODERATOR'    => 'Moderator',  // Your board has 1 moderator
2432      'MODERATORS'    => 'Moderators', // Your board has multiple moderators
2433      ...</pre>
2434      </div>
2435  
2436      <a name="writingstyle"></a><h3>6.v. Writing Style</h3>
2437  
2438      <h4>Miscellaneous tips &amp; hints:</h4>
2439  
2440      <p>As the language files are PHP files, where the various strings for phpBB are stored within an array which in turn are used for display within an HTML page, rules of syntax for both must be considered. Potentially problematic characters are: <code>'</code> (straight quote/apostrophe), <code>&quot;</code> (straight double quote), <code>&lt;</code> (less-than sign), <code>&gt;</code> (greater-than sign) and <code>&amp;</code> (ampersand).</p>
2441  
2442      <p class="bad">// Bad - The un-escapsed straight-quote/apostrophe will throw a PHP parse error</p>
2443  
2444      <div class="codebox"><pre>
2445      ...
2446  'CONV_ERROR_NO_AVATAR_PATH'
2447      =&gt;    'Note to developer: you must specify $convertor['avatar_path'] to use %s.',
2448      ...</pre>
2449      </div>
2450  
2451      <p class="good">// Good - Literal straight quotes should be escaped with a backslash, ie: \</p>
2452  
2453      <div class="codebox"><pre>
2454      ...
2455  'CONV_ERROR_NO_AVATAR_PATH'
2456      =&gt;    'Note to developer: you must specify $convertor[\'avatar_path\'] to use %s.',
2457      ...</pre>
2458      </div>
2459  
2460      <p>However, because phpBB3 now uses UTF-8 as its sole encoding, we can actually use this to our advantage and not have to remember to escape a straight quote when we don't have to:</p>
2461  
2462      <p class="bad">// Bad - The un-escapsed straight-quote/apostrophe will throw a PHP parse error</p>
2463  
2464      <div class="codebox"><pre>
2465      ...
2466  'USE_PERMISSIONS'    =&gt;    'Test out user's permissions',
2467      ...</pre>
2468      </div>
2469  
2470      <p class="good">// Okay - However, non-programmers wouldn't type "user\'s" automatically</p>
2471  
2472      <div class="codebox"><pre>
2473      ...
2474  'USE_PERMISSIONS'    =&gt;    'Test out user\'s permissions',
2475      ...</pre>
2476      </div>
2477  
2478      <p class="good">// Best - Use the Unicode Right-Single-Quotation-Mark character</p>
2479  
2480      <div class="codebox"><pre>
2481      ...
2482  'USE_PERMISSIONS'    =&gt;    'Test out user&rsquo;s permissions',
2483      ...</pre>
2484      </div>
2485  
2486      <p>The <code>&quot;</code> (straight double quote), <code>&lt;</code> (less-than sign) and <code>&gt;</code> (greater-than sign) characters can all be used as displayed glyphs or as part of HTML markup, for example:</p>
2487  
2488      <p class="bad">// Bad - Invalid HTML, as segments not part of elements are not entitised</p>
2489  
2490      <div class="codebox"><pre>
2491      ...
2492  'FOO_BAR'    =&gt;    'PHP version &lt; 5.3.3.&lt;br /&gt;
2493      Visit &quot;Downloads&quot; at &lt;a href=&quot;http://www.php.net/&quot;&gt;www.php.net&lt;/a&gt;.',
2494      ...</pre>
2495      </div>
2496  
2497      <p class="good">// Okay - No more invalid HTML, but &quot;&amp;quot;&quot; is rather clumsy</p>
2498  
2499      <div class="codebox"><pre>
2500      ...
2501  'FOO_BAR'    =&gt;    'PHP version &amp;lt; 5.3.3.&lt;br /&gt;
2502      Visit &amp;quot;Downloads&amp;quot; at &lt;a href=&quot;http://www.php.net/&quot;&gt;www.php.net&lt;/a&gt;.',
2503      ...</pre>
2504      </div>
2505  
2506      <p class="good">// Best - No more invalid HTML, and usage of correct typographical quotation marks</p>
2507  
2508      <div class="codebox"><pre>
2509      ...
2510  'FOO_BAR'    =&gt;    'PHP version &amp;lt; 5.3.3.&lt;br /&gt;
2511      Visit &ldquo;Downloads&rdquo; at &lt;a href=&quot;http://www.php.net/&quot;&gt;www.php.net&lt;/a&gt;.',
2512      ...</pre>
2513      </div>
2514  
2515      <p>Lastly, the <code>&amp;</code> (ampersand) must always be entitised regardless of where it is used:</p>
2516  
2517      <p class="bad">// Bad - Invalid HTML, none of the ampersands are entitised</p>
2518  
2519      <div class="codebox"><pre>
2520      ...
2521  'FOO_BAR'    =&gt;    '&lt;a href=&quot;http://somedomain.tld/?foo=1&amp;bar=2&quot;&gt;Foo &amp; Bar&lt;/a&gt;.',
2522      ...</pre>
2523      </div>
2524  
2525      <p class="good">// Good - Valid HTML, amperands are correctly entitised in all cases</p>
2526  
2527      <div class="codebox"><pre>
2528      ...
2529  'FOO_BAR'    =&gt;    '&lt;a href=&quot;http://somedomain.tld/?foo=1&amp;amp;bar=2&quot;&gt;Foo &amp;amp; Bar&lt;/a&gt;.',
2530      ...</pre>
2531      </div>
2532  
2533      <p>As for how these charcters are entered depends very much on choice of Operating System, current language locale/keyboard configuration and native abilities of the text editor used to edit phpBB language files. Please see <a href="http://en.wikipedia.org/wiki/Unicode#Input_methods">http://en.wikipedia.org/wiki/Unicode#Input_methods</a> for more information.</p>
2534  
2535      <h4>Spelling, punctuation, grammar, et cetera:</h4>
2536  
2537      <p>The default language pack bundled with phpBB is <strong>British English</strong> using <a href="http://www.cambridge.org/">Cambridge University Press</a> spelling and is assigned the language code <code>en</code>. The style and tone of writing tends towards formal and translations <strong>should</strong> emulate this style, at least for the variant using the most compact language code. Less formal translations or those with colloquialisms <strong>must</strong> be denoted as such via either an <code>extension</code> or <code>privateuse</code> tag within its language code.</p>
2538  
2539          </div>
2540  
2541          <div class="back2top"><a href="#wrap" class="top">Back to Top</a></div>
2542  
2543          </div>
2544      </div>
2545  
2546      <hr />
2547  
2548  <a name="disclaimer"></a><h2>7. Copyright and disclaimer</h2>
2549  
2550      <div class="paragraph">
2551          <div class="inner">
2552  
2553          <div class="content">
2554  
2555      <p>phpBB is free software, released under the terms of the <a href="http://opensource.org/licenses/gpl-2.0.php">GNU General Public License, version 2 (GPL-2.0)</a>. Copyright © <a href="https://www.phpbb.com">phpBB Limited</a>. For full copyright and license information, please see the docs/CREDITS.txt file.</p>
2556  
2557          </div>
2558  
2559          <div class="back2top"><a href="#wrap" class="top">Back to Top</a></div>
2560  
2561          </div>
2562      </div>
2563  
2564  <!-- END DOCUMENT -->
2565  
2566      <div id="page-footer">
2567          <div class="version">&nbsp;</div>
2568      </div>
2569  </div></div>
2570  
2571  <div>
2572      <a id="bottom" accesskey="z"></a>
2573  </div>
2574  
2575  </body>
2576  </html>


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