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Derek Jones8917af72010-03-05 12:41:45 -0600[diff] [blame]37<td><h1>CodeIgniter User Guide Version 2.0.0</h1></td>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]38<td id="breadcrumb_right"><a href="../toc.html">Table of Contents Page</a></td>
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43
44
45<!-- START BREADCRUMB -->
46<table cellpadding="0" cellspacing="0" border="0" style="width:100%">
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49<a href="http://codeigniter.com/">CodeIgniter Home</a> &nbsp;&#8250;&nbsp;
50<a href="../index.html">User Guide Home</a> &nbsp;&#8250;&nbsp;
51Style Guide
52</td>
53<td id="searchbox"><form method="get" action="http://www.google.com/search"><input type="hidden" name="as_sitesearch" id="as_sitesearch" value="codeigniter.com/user_guide/" />Search User Guide&nbsp; <input type="text" class="input" style="width:200px;" name="q" id="q" size="31" maxlength="255" value="" />&nbsp;<input type="submit" class="submit" name="sa" value="Go" /></form></td>
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59
60
61<!-- START CONTENT -->
62<div id="content">
63
64
65<h1>General Style and Syntax</h1>
66
Derek Allardf3c4f272009-09-22 11:53:34 +0000[diff] [blame]67<p>The following page describes the use of coding rules adhered to when developing CodeIgniter.</p>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]68
69
70<h2>Table of Contents</h2>
71<ul class="minitoc">
Derek Jones9babd662008-11-14 02:09:00 +0000[diff] [blame]72 <li><a href="#file_format">File Format</a></li>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]73 <li><a href="#php_closing_tag">PHP Closing Tag</a></li>
74 <li><a href="#class_and_method_naming">Class and Method Naming</a></li>
75 <li><a href="#variable_names">Variable Names</a></li>
76 <li><a href="#commenting">Commenting</a></li>
77 <li><a href="#constants">Constants</a></li>
78 <li><a href="#true_false_and_null">TRUE, FALSE, and NULL</a></li>
79 <li><a href="#logical_operators">Logical Operators</a></li>
80 <li><a href="#comparing_return_values_and_typecasting">Comparing Return Values and Typecasting</a></li>
81 <li><a href="#debugging_code">Debugging Code</a></li>
82 <li><a href="#whitespace_in_files">Whitespace in Files</a></li>
83 <li><a href="#compatibility">Compatibility</a></li>
84 <li><a href="#class_and_file_names_using_common_words">Class and File Names using Common Words</a></li>
85 <li><a href="#database_table_names">Database Table Names</a></li>
86 <li><a href="#one_file_per_class">One File per Class</a></li>
87 <li><a href="#whitespace">Whitespace</a></li>
88 <li><a href="#line_breaks">Line Breaks</a></li>
89 <li><a href="#code_indenting">Code Indenting</a></li>
90 <li><a href="#bracket_spacing">Bracket and Parenthetic Spacing</li>
Derek Allard2f304d62010-07-05 07:40:26 -0400[diff] [blame]91 <li><a href="#localized_text">Localized Text</a></li>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]92 <li><a href="#private_methods_and_variables">Private Methods and Variables</a></li>
93 <li><a href="#php_errors">PHP Errors</a></li>
94 <li><a href="#short_open_tags">Short Open Tags</a></li>
95 <li><a href="#one_statement_per_line">One Statement Per Line</a></li>
96 <li><a href="#strings">Strings</a></li>
97 <li><a href="#sql_queries">SQL Queries</a></li>
98 <li><a href="#default_function_arguments">Default Function Arguments</a></li>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]99</ul>
100
Derek Jones9babd662008-11-14 02:09:00 +0000[diff] [blame]101<li>
102
103 <h2><a name="file_format"></a>File Format</h2>
104 <div class="guidelineDetails">
105 <p>Files should be saved with Unicode (UTF-8) encoding. The <abbr title="Byte Order Mark">BOM</abbr>
106 should <em>not</em> be used. Unlike UTF-16 and UTF-32, there's no byte order to indicate in
107 a UTF-8 encoded file, and the <abbr title="Byte Order Mark">BOM</abbr> can have a negative side effect in PHP of sending output,
108 preventing the application from being able to set its own headers. Unix line endings should
109 be used (LF).</p>
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]110
Derek Jones9babd662008-11-14 02:09:00 +0000[diff] [blame]111 <p>Here is how to apply these settings in some of the more common text editors. Instructions for your
112 text editor may vary; check your text editor's documentation.</p>
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]113
Derek Jones9babd662008-11-14 02:09:00 +0000[diff] [blame]114 <h5>TextMate</h5>
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]115
Derek Jones9babd662008-11-14 02:09:00 +0000[diff] [blame]116 <ol>
117 <li>Open the Application Preferences</li>
118 <li>Click Advanced, and then the "Saving" tab</li>
119 <li>In "File Encoding", select "UTF-8 (recommended)"</li>
120 <li>In "Line Endings", select "LF (recommended)"</li>
121 <li><em>Optional:</em> Check "Use for existing files as well" if you wish to modify the line
122 endings of files you open to your new preference.</li>
123 </ol>
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]124
Derek Jones9babd662008-11-14 02:09:00 +0000[diff] [blame]125 <h5>BBEdit</h5>
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]126
Derek Jones9babd662008-11-14 02:09:00 +0000[diff] [blame]127 <ol>
128 <li>Open the Application Preferences</li>
129 <li>Select "Text Encodings" on the left.</li>
130 <li>In "Default text encoding for new documents", select "Unicode (UTF-8, no BOM)"</li>
131 <li><em>Optional:</em> In "If file's encoding can't be guessed, use", select
132 "Unicode (UTF-8, no BOM)"</li>
133 <li>Select "Text Files" on the left.</li>
134 <li>In "Default line breaks", select "Mac OS X and Unix (LF)"</li>
135 </ol>
136 </div>
137
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]138 <h2><a name="php_closing_tag"></a>PHP Closing Tag</h2>
139 <div class="guidelineDetails">
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]140 <p>The PHP closing tag on a PHP document <strong>?&gt;</strong> is optional to the PHP parser. However, if used, any whitespace following the closing tag, whether introduced
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]141 by the developer, user, or an FTP application, can cause unwanted output, PHP errors, or if the latter are suppressed, blank pages. For this reason, all PHP files should
142 <strong>OMIT</strong> the closing PHP tag, and instead use a comment block to mark the end of file and it's location relative to the application root.
143 This allows you to still identify a file as being complete and not truncated.</p>
144<code><strong>INCORRECT</strong>:
145&lt;?php
146
147echo "Here's my code!";
148
149?&gt;
150
151<strong>CORRECT</strong>:
152&lt;?php
153
154echo "Here's my code!";
155
156/* End of file myfile.php */
157/* Location: ./system/modules/mymodule/myfile.php */
158</code>
159 </div>
160
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]161
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]162 <h2><a name="class_and_method_naming"></a>Class and Method Naming</h2>
163 <div class="guidelineDetails">
164 <p>Class names should always have their first letter uppercase, and the constructor method should match identically. Multiple words should be separated with an underscore, and not CamelCased. All other class methods should be entirely lowercased and named to clearly indicate their function, preferably including a verb. Try to avoid overly long and verbose names.</p>
165
166 <code><strong>INCORRECT</strong>:
167class superclass
168class SuperClass
169
170<strong>CORRECT</strong>:
171class Super_class</code>
172
173 <p>Notice that the Class and constructor methods are identically named and cased:</p>
174
175 <code>class Super_class {
176
177 function Super_class()
178 {
179
180 }
181}</code>
182
183 <p>Examples of improper and proper method naming:</p>
184
185 <code><strong>INCORRECT</strong>:
186function fileproperties() // not descriptive and needs underscore separator
187function fileProperties() // not descriptive and uses CamelCase
188function getfileproperties() // Better! But still missing underscore separator
189function getFileProperties() // uses CamelCase
190function get_the_file_properties_from_the_file() // wordy
191
192<strong>CORRECT</strong>:
193function get_file_properties() // descriptive, underscore separator, and all lowercase letters</code>
194
195 </div>
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]196
197
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]198 <h2><a name="variable_names"></a>Variable Names</h2>
199 <div class="guidelineDetails">
200 <p>The guidelines for variable naming is very similar to that used for class methods. Namely, variables should contain only lowercase letters, use underscore separators, and be reasonably named to indicate their purpose and contents. Very short, non-word variables should only be used as iterators in for() loops.</p>
201<code><strong>INCORRECT</strong>:
202$j = &apos;foo&apos;; // single letter variables should only be used in for() loops
203$Str // contains uppercase letters
204$bufferedText // uses CamelCasing, and could be shortened without losing semantic meaning
205$groupid // multiple words, needs underscore separator
206$name_of_last_city_used // too long
207
208<strong>CORRECT</strong>:
209for ($j = 0; $j &lt; 10; $j++)
210$str
211$buffer
212$group_id
213$last_city
214</code>
215 </div>
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]216
217
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]218 <h2><a name="commenting"></a>Commenting</h2>
219 <div class="guidelineDetails">
220 <p>In general, code should be commented prolifically. It not only helps describe the flow and intent of the code for less experienced programmers, but can prove invaluable when returning to your own code months down the line. There is not a required format for comments, but the following are recommended.</p>
221
222 <p><a href="http://manual.phpdoc.org/HTMLSmartyConverter/HandS/phpDocumentor/tutorial_phpDocumentor.howto.pkg.html#basics.docblock">DocBlock</a> style comments preceding class and method declarations so they can be picked up by IDEs:</p>
223
224<code>/**
225 * Super Class
226 *
227 * @package Package Name
228 * @subpackage Subpackage
229 * @category Category
230 * @author Author Name
231 * @link http://example.com
232 */
233class Super_class {</code>
234
235<code>/**
236 * Encodes string for use in XML
237 *
238 * @access public
239 * @param string
240 * @return string
241 */
242function xml_encode($str)</code>
243
244 <p>Use single line comments within code, leaving a blank line between large comment blocks and code.</p>
245
246<code>// break up the string by newlines
247$parts = explode("\n", $str);
248
249// A longer comment that needs to give greater detail on what is
250// occurring and why can use multiple single-line comments. Try to
251// keep the width reasonable, around 70 characters is the easiest to
252// read. Don't hesitate to link to permanent external resources
253// that may provide greater detail:
254//
255// http://example.com/information_about_something/in_particular/
256
257$parts = $this->foo($parts);
258</code>
259 </div>
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]260
261
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]262 <h2><a name="constants"></a>Constants</h2>
263 <div class="guidelineDetails">
Derek Allard5a8a4552009-08-17 18:06:30 +0000[diff] [blame]264 <p>Constants follow the same guidelines as do variables, except constants should always be fully uppercase. <em>Always use CodeIgniter constants when appropriate, i.e. SLASH, LD, RD, PATH_CACHE, etc.</em></p>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]265<code><strong>INCORRECT</strong>:
266myConstant // missing underscore separator and not fully uppercase
267N // no single-letter constants
268S_C_VER // not descriptive
269$str = str_replace('{foo}', 'bar', $str); // should use LD and RD constants
270
271<strong>CORRECT</strong>:
272MY_CONSTANT
273NEWLINE
274SUPER_CLASS_VERSION
275$str = str_replace(LD.'foo'.RD, 'bar', $str);
276</code>
277 </div>
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]278
279
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]280 <h2><a name="true_false_and_null"></a>TRUE, FALSE, and NULL</h2>
281 <div class="guidelineDetails">
282 <p><strong>TRUE</strong>, <strong>FALSE</strong>, and <strong>NULL</strong> keywords should always be fully uppercase.</p>
283<code><strong>INCORRECT</strong>:
284if ($foo == true)
285$bar = false;
286function foo($bar = null)
287
288<strong>CORRECT</strong>:
289if ($foo == TRUE)
290$bar = FALSE;
291function foo($bar = NULL)</code>
292 </div>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]293
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]294
295
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]296 <h2><a name="logical_operators"></a>Logical Operators</h2>
297 <div class="guidelineDetails">
298 <p>Use of <strong>||</strong> is discouraged as its clarity on some output devices is low (looking like the number 11 for instance).
299 <strong>&amp;&amp;</strong> is preferred over <strong>AND</strong> but either are acceptable, and a space should always precede and follow <strong>!</strong>.</p>
300<code><strong>INCORRECT</strong>:
301if ($foo || $bar)
302if ($foo AND $bar) // okay but not recommended for common syntax highlighting applications
303if (!$foo)
304if (! is_array($foo))
305
306<strong>CORRECT</strong>:
307if ($foo OR $bar)
308if ($foo && $bar) // recommended
309if ( ! $foo)
310if ( ! is_array($foo))
311</code>
312 </div>
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]313
314
315
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]316 <h2><a name="comparing_return_values_and_typecasting"></a>Comparing Return Values and Typecasting</h2>
317 <div class="guidelineDetails">
318 <p>Some PHP functions return FALSE on failure, but may also have a valid return value of "" or 0, which would evaluate to FALSE in loose comparisons. Be explicit by comparing the variable type when using these return values in conditionals to ensure the return value is indeed what you expect, and not a value that has an equivalent loose-type evaluation.</p>
319 <p>Use the same stringency in returning and checking your own variables. Use <strong>===</strong> and <strong>!==</strong> as necessary.
320
321<code><strong>INCORRECT</strong>:
322// If 'foo' is at the beginning of the string, strpos will return a 0,
323// resulting in this conditional evaluating as TRUE
324if (strpos($str, 'foo') == FALSE)
325
326<strong>CORRECT</strong>:
327if (strpos($str, 'foo') === FALSE)
328</code>
329
330<code><strong>INCORRECT</strong>:
331function build_string($str = "")
332{
333 if ($str == "") // uh-oh! What if FALSE or the integer 0 is passed as an argument?
334 {
335
336 }
337}
338
339<strong>CORRECT</strong>:
340function build_string($str = "")
341{
342 if ($str === "")
343 {
344
345 }
346}</code>
347
348 <p>See also information regarding <a href="http://us3.php.net/manual/en/language.types.type-juggling.php#language.types.typecasting">typecasting</a>, which can be quite useful. Typecasting has a slightly different effect which may be desirable. When casting a variable as a string, for instance, NULL and boolean FALSE variables become empty strings, 0 (and other numbers) become strings of digits, and boolean TRUE becomes "1":</p>
349
350<code>$str = (string) $str; // cast $str as a string</code>
351
352 </div>
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]353
354
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]355 <h2><a name="debugging_code"></a>Debugging Code</h2>
356 <div class="guidelineDetails">
357 <p>No debugging code can be left in place for submitted add-ons unless it is commented out, i.e. no var_dump(), print_r(), die(), and exit() calls that were used while creating the add-on, unless they are commented out.</p>
358
359<code>// print_r($foo);</code>
360 </div>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]361
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]362
363
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]364 <h2><a name="whitespace_in_files"></a>Whitespace in Files</h2>
365 <div class="guidelineDetails">
Derek Allard5a8a4552009-08-17 18:06:30 +0000[diff] [blame]366 <p>No whitespace can precede the opening PHP tag or follow the closing PHP tag. Output is buffered, so whitespace in your files can cause output to begin before CodeIgniter outputs its content, leading to errors and an inability for CodeIgniter to send proper headers. In the examples below, select the text with your mouse to reveal the incorrect whitespace.</p>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]367
368 <p><strong>INCORRECT</strong>:</p>
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]369<code>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]370&lt;?php
371 // ...there is whitespace and a linebreak above the opening PHP tag
372 // as well as whitespace after the closing PHP tag
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]373?&gt;
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]374</code>
375 <p><strong>CORRECT</strong>:</p>
376<code>&lt;?php
377 // this sample has no whitespace before or after the opening and closing PHP tags
378?&gt;</code>
379
380 </div>
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]381
382
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]383 <h2><a name="compatibility"></a>Compatibility</h2>
384 <div class="guidelineDetails">
385 <p>Unless specifically mentioned in your add-on's documentation, all code must be compatible with PHP version 4.3+. Additionally, do not use PHP functions that require non-default libraries to be installed unless your code contains an alternative method when the function is not available, or you implicitly document that your add-on requires said PHP libraries.</p>
386 </div>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]387
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]388
389
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]390 <h2><a name="class_and_file_names_using_common_words"></a>Class and File Names using Common Words</h2>
391 <div class="guidelineDetails">
392 <p>When your class or filename is a common word, or might quite likely be identically named in another PHP script, provide a unique prefix to help prevent collision. Always realize that your end users may be running other add-ons or third party PHP scripts. Choose a prefix that is unique to your identity as a developer or company.</p>
393
394<code><strong>INCORRECT</strong>:
395class Email pi.email.php
396class Xml ext.xml.php
397class Import mod.import.php
398
399<strong>CORRECT</strong>:
400class Pre_email pi.pre_email.php
401class Pre_xml ext.pre_xml.php
402class Pre_import mod.pre_import.php
403</code>
404 </div>
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]405
406
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]407 <h2><a name="database_table_names"></a>Database Table Names</h2>
408 <div class="guidelineDetails">
Derek Allard5a8a4552009-08-17 18:06:30 +0000[diff] [blame]409 <p>Any tables that your add-on might use must use the 'exp_' prefix, followed by a prefix uniquely identifying you as the developer or company, and then a short descriptive table name. You do not need to be concerned about the database prefix being used on the user's installation, as CodeIgniter's database class will automatically convert 'exp_' to what is actually being used.</p>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]410
411<code><strong>INCORRECT</strong>:
412email_addresses // missing both prefixes
413pre_email_addresses // missing exp_ prefix
414exp_email_addresses // missing unique prefix
415
416<strong>CORRECT</strong>:
417exp_pre_email_addresses
418</code>
419
420 <p class="important"><strong>NOTE:</strong> Be mindful that MySQL has a limit of 64 characters for table names. This should not be an issue as table names that would exceed this would likely have unreasonable names. For instance, the following table name exceeds this limitation by one character. Silly, no? <strong>exp_pre_email_addresses_of_registered_users_in_seattle_washington</strong>
421 </div>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]422
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]423
424
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]425 <h2><a name="one_file_per_class"></a>One File per Class</h2>
426 <div class="guidelineDetails">
Derek Allard5a8a4552009-08-17 18:06:30 +0000[diff] [blame]427 <p>Use separate files for each class your add-on uses, unless the classes are <em>closely related</em>. An example of CodeIgniter files that contains multiple classes is the Database class file, which contains both the DB class and the DB_Cache class, and the Magpie plugin, which contains both the Magpie and Snoopy classes.</p>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]428 </div>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]429
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]430
431
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]432 <h2><a name="whitespace"></a>Whitespace</h2>
433 <div class="guidelineDetails">
434 <p>Use tabs for whitespace in your code, not spaces. This may seem like a small thing, but using tabs instead of whitespace allows the developer looking at your code to have indentation at levels that they prefer and customize in whatever application they use. And as a side benefit, it results in (slightly) more compact files, storing one tab character versus, say, four space characters.</p>
435 </div>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]436
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]437
438
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]439 <h2><a name="line_breaks"></a>Line Breaks</h2>
440 <div class="guidelineDetails">
441 <p>Files must be saved with Unix line breaks. This is more of an issue for developers who work in Windows, but in any case ensure that your text editor is setup to save files with Unix line breaks.</p>
442 </div>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]443
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]444
445
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]446 <h2><a name="code_indenting"></a>Code Indenting</h2>
447 <div class="guidelineDetails">
448 <p>Use Allman style indenting. With the exception of Class declarations, braces are always placed on a line by themselves, and indented at the same level as the control statement that "owns" them.</p>
449
450<code><strong>INCORRECT</strong>:
451function foo($bar) {
452 // ...
453}
454
455foreach ($arr as $key => $val) {
456 // ...
457}
458
459if ($foo == $bar) {
460 // ...
461} else {
462 // ...
463}
464
465for ($i = 0; $i &lt; 10; $i++)
466 {
467 for ($j = 0; $j &lt; 10; $j++)
468 {
469 // ...
470 }
471 }
472
473<strong>CORRECT</strong>:
474function foo($bar)
475{
476 // ...
477}
478
479foreach ($arr as $key => $val)
480{
481 // ...
482}
483
484if ($foo == $bar)
485{
486 // ...
487}
488else
489{
490 // ...
491}
492
493for ($i = 0; $i &lt; 10; $i++)
494{
495 for ($j = 0; $j &lt; 10; $j++)
496 {
497 // ...
498 }
499}</code>
500 </div>
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]501
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]502
503 <h2><a name="bracket_spacing"></a>Bracket and Parenthetic Spacing</h2>
504 <div class="guidelineDetails">
505 <p>In general, parenthesis and brackets should not use any additional spaces. The exception is that a space should always follow PHP control structures that accept arguments with parenthesis (declare, do-while, elseif, for, foreach, if, switch, while), to help distinguish them from functions and increase readability.</p>
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]506
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]507<code>INCORRECT:
508$arr[ $foo ] = 'foo';
509
510CORRECT:
511$arr[$foo] = 'foo'; // no spaces around array keys
512
513
514INCORRECT:
515function foo ( $bar )
516{
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]517
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]518}
519
520CORRECT:
521function foo($bar) // no spaces around parenthesis in function declarations
522{
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]523
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]524}
525
526
527INCORRECT:
528foreach( $query->result() as $row )
529
530CORRECT:
531foreach ($query->result() as $row) // single space following PHP control structures, but not in interior parenthesis
532</code>
533 </div>
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]534
535
536
Derek Allard2f304d62010-07-05 07:40:26 -0400[diff] [blame]537 <h2><a name="localized_text"></a>Localized Text</h2>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]538 <div class="guidelineDetails">
Derek Allard2f304d62010-07-05 07:40:26 -0400[diff] [blame]539 <p>Any text that is output in the control panel should use language variables in your lang file to allow localization.</p>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]540
541<code>INCORRECT:
542return "Invalid Selection";
543
544CORRECT:
Derek Allard2f304d62010-07-05 07:40:26 -0400[diff] [blame]545return $this->lang->line('invalid_selection');</code>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]546 </div>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]547
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]548
549
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]550 <h2><a name="private_methods_and_variables"></a>Private Methods and Variables</h2>
551 <div class="guidelineDetails">
552 <p>Methods and variables that are only accessed internally by your class, such as utility and helper functions that your public methods use for code abstraction, should be prefixed with an underscore.</p>
553
554<code>convert_text() // public method
555_convert_text() // private method</code>
556 </div>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]557
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]558
559
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]560 <h2><a name="php_errors"></a>PHP Errors</h2>
561 <div class="guidelineDetails">
562 <p>Code must run error free and not rely on warnings and notices to be hidden to meet this requirement. For instance, never access a variable that you did not set yourself (such as $_POST array keys) without first checking to see that it isset().</p>
563
564 <p>Make sure that while developing your add-on, error reporting is enabled for ALL users, and that display_errors is enabled in the PHP environment. You can check this setting with:</p>
565
566<code>if (ini_get('display_errors') == 1)
567{
568 exit "Enabled";
569}</code>
570
571 <p>On some servers where display_errors is disabled, and you do not have the ability to change this in the php.ini, you can often enable it with:</p>
572
573<code>ini_set('display_errors', 1);</code>
574
575 <p class="important"><strong>NOTE:</strong> Setting the <a href="http://us.php.net/manual/en/ref.errorfunc.php#ini.display-errors">display_errors</a> setting with ini_set() at runtime is not identical to having it enabled in the PHP environment. Namely, it will not have any effect if the script has fatal errors</p>
576 </div>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]577
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]578
579
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]580 <h2><a name="short_open_tags"></a>Short Open Tags</h2>
581 <div class="guidelineDetails">
582 <p>Always use full PHP opening tags, in case a server does not have short_open_tag enabled.</p>
583
584<code><strong>INCORRECT</strong>:
585&lt;? echo $foo; ?&gt;
586
587&lt;?=$foo?&gt;
588
589<strong>CORRECT</strong>:
590&lt;?php echo $foo; ?&gt;</code>
591 </div>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]592
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]593
594
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]595 <h2><a name="one_statement_per_line"></a>One Statement Per Line</h2>
596 <div class="guidelineDetails">
597 <p>Never combine statements on one line.</p>
598
599<code><strong>INCORRECT</strong>:
600$foo = 'this'; $bar = 'that'; $bat = str_replace($foo, $bar, $bag);
601
602<strong>CORRECT</strong>:
603$foo = 'this';
604$bar = 'that';
605$bat = str_replace($foo, $bar, $bag);
606</code>
607 </div>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]608
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]609
610
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]611 <h2><a name="strings"></a>Strings</h2>
612 <div class="guidelineDetails">
613 <p>Always use single quoted strings unless you need variables parsed, and in cases where you do need variables parsed, use braces to prevent greedy token parsing. You may also use double-quoted strings if the string contains single quotes, so you do not have to use escape characters.</p>
614
615<code><strong>INCORRECT</strong>:
616"My String" // no variable parsing, so no use for double quotes
617"My string $foo" // needs braces
618'SELECT foo FROM bar WHERE baz = \'bag\'' // ugly
619
620<strong>CORRECT</strong>:
621'My String'
622"My string {$foo}"
623"SELECT foo FROM bar WHERE baz = 'bag'"</code>
624 </div>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]625
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]626
627
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]628 <h2><a name="sql_queries"></a>SQL Queries</h2>
629 <div class="guidelineDetails">
630 <p>MySQL keywords are always capitalized: SELECT, INSERT, UPDATE, WHERE, AS, JOIN, ON, IN, etc.</p>
631
632 <p>Break up long queries into multiple lines for legibility, preferably breaking for each clause.</p>
633
634<code><strong>INCORRECT</strong>:
635// keywords are lowercase and query is too long for
636// a single line (... indicates continuation of line)
637$query = $this->db->query("select foo, bar, baz, foofoo, foobar as raboof, foobaz from exp_pre_email_addresses
638...where foo != 'oof' and baz != 'zab' order by foobaz limit 5, 100");
639
640<strong>CORRECT</strong>:
641$query = $this->db->query("SELECT foo, bar, baz, foofoo, foobar AS raboof, foobaz
642 FROM exp_pre_email_addresses
643 WHERE foo != 'oof'
644 AND baz != 'zab'
645 ORDER BY foobaz
646 LIMIT 5, 100");</code>
647 </div>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]648
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]649
650
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]651 <h2><a name="default_function_arguments"></a>Default Function Arguments</h2>
652 <div class="guidelineDetails">
653 <p>Whenever appropriate, provide function argument defaults, which helps prevent PHP errors with mistaken calls and provides common fallback values which can save a few lines of code. Example:</p>
654
655<code>function foo($bar = '', $baz = FALSE)</code>
656 </div>
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]657
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]658
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]659
660</div>
661
662
663
664</div>
665<!-- END CONTENT -->
666
667
668<div id="footer">
669<p>
670Previous Topic:&nbsp;&nbsp;<a href="security.html">Security</a>
671&nbsp;&nbsp;&nbsp;&middot;&nbsp;&nbsp;
672<a href="#top">Top of Page</a>&nbsp;&nbsp;&nbsp;&middot;&nbsp;&nbsp;
673<a href="../index.html">User Guide Home</a>&nbsp;&nbsp;&nbsp;&middot;&nbsp;&nbsp;
674Next Topic:&nbsp;&nbsp;<a href="../doc_style/index.html">Writing Documentation</a>
675</p>
Derek Jonesd6d70e32010-03-29 10:10:27 -0500[diff] [blame]676<p><a href="http://codeigniter.com">CodeIgniter</a> &nbsp;&middot;&nbsp; Copyright &#169; 2006-2010 &nbsp;&middot;&nbsp; <a href="http://ellislab.com/">EllisLab, Inc.</a></p>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]677</div>
678
679</body>
Rick Ellis5a9fd7a2008-08-31 05:58:32 +0000[diff] [blame]680</html>