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Pascal Kriete1f622292011-04-07 12:06:51 -0400[diff] [blame^]37<td><h1>CodeIgniter User Guide Version 2.0.2</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>
39</tr>
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41</div>
42<!-- END NAVIGATION -->
43
44
45<!-- START BREADCRUMB -->
46<table cellpadding="0" cellspacing="0" border="0" style="width:100%">
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48<td id="breadcrumb">
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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57
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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">
Pascal Krietee79d41a2010-11-10 16:41:23 -0500[diff] [blame]164 <p>Class names should always start with an uppercase letter. 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>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]165
166 <code><strong>INCORRECT</strong>:
167class superclass
168class SuperClass
169
170<strong>CORRECT</strong>:
171class Super_class</code>
172
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]173
174 <code>class Super_class {
175
Pascal Krietee79d41a2010-11-10 16:41:23 -0500[diff] [blame]176 function __construct()
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]177 {
178
179 }
180}</code>
181
182 <p>Examples of improper and proper method naming:</p>
183
184 <code><strong>INCORRECT</strong>:
185function fileproperties() // not descriptive and needs underscore separator
186function fileProperties() // not descriptive and uses CamelCase
187function getfileproperties() // Better! But still missing underscore separator
188function getFileProperties() // uses CamelCase
189function get_the_file_properties_from_the_file() // wordy
190
191<strong>CORRECT</strong>:
192function get_file_properties() // descriptive, underscore separator, and all lowercase letters</code>
193
194 </div>
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]195
196
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]197 <h2><a name="variable_names"></a>Variable Names</h2>
198 <div class="guidelineDetails">
199 <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>
200<code><strong>INCORRECT</strong>:
201$j = &apos;foo&apos;; // single letter variables should only be used in for() loops
202$Str // contains uppercase letters
203$bufferedText // uses CamelCasing, and could be shortened without losing semantic meaning
204$groupid // multiple words, needs underscore separator
205$name_of_last_city_used // too long
206
207<strong>CORRECT</strong>:
208for ($j = 0; $j &lt; 10; $j++)
209$str
210$buffer
211$group_id
212$last_city
213</code>
214 </div>
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]215
216
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]217 <h2><a name="commenting"></a>Commenting</h2>
218 <div class="guidelineDetails">
219 <p>In general, code should be commented prolifically. It not only helps describe the flow and intent of the code for less experienced programmers, but can prove invaluable when returning to your own code months down the line. There is not a required format for comments, but the following are recommended.</p>
220
221 <p><a href="http://manual.phpdoc.org/HTMLSmartyConverter/HandS/phpDocumentor/tutorial_phpDocumentor.howto.pkg.html#basics.docblock">DocBlock</a> style comments preceding class and method declarations so they can be picked up by IDEs:</p>
222
223<code>/**
224 * Super Class
225 *
226 * @package Package Name
227 * @subpackage Subpackage
228 * @category Category
229 * @author Author Name
230 * @link http://example.com
231 */
232class Super_class {</code>
233
234<code>/**
235 * Encodes string for use in XML
236 *
237 * @access public
238 * @param string
239 * @return string
240 */
241function xml_encode($str)</code>
242
243 <p>Use single line comments within code, leaving a blank line between large comment blocks and code.</p>
244
245<code>// break up the string by newlines
246$parts = explode("\n", $str);
247
248// A longer comment that needs to give greater detail on what is
249// occurring and why can use multiple single-line comments. Try to
250// keep the width reasonable, around 70 characters is the easiest to
251// read. Don't hesitate to link to permanent external resources
252// that may provide greater detail:
253//
254// http://example.com/information_about_something/in_particular/
255
256$parts = $this->foo($parts);
257</code>
258 </div>
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]259
260
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]261 <h2><a name="constants"></a>Constants</h2>
262 <div class="guidelineDetails">
Derek Allard5a8a4552009-08-17 18:06:30 +0000[diff] [blame]263 <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]264<code><strong>INCORRECT</strong>:
265myConstant // missing underscore separator and not fully uppercase
266N // no single-letter constants
267S_C_VER // not descriptive
268$str = str_replace('{foo}', 'bar', $str); // should use LD and RD constants
269
270<strong>CORRECT</strong>:
271MY_CONSTANT
272NEWLINE
273SUPER_CLASS_VERSION
274$str = str_replace(LD.'foo'.RD, 'bar', $str);
275</code>
276 </div>
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]277
278
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]279 <h2><a name="true_false_and_null"></a>TRUE, FALSE, and NULL</h2>
280 <div class="guidelineDetails">
281 <p><strong>TRUE</strong>, <strong>FALSE</strong>, and <strong>NULL</strong> keywords should always be fully uppercase.</p>
282<code><strong>INCORRECT</strong>:
283if ($foo == true)
284$bar = false;
285function foo($bar = null)
286
287<strong>CORRECT</strong>:
288if ($foo == TRUE)
289$bar = FALSE;
290function foo($bar = NULL)</code>
291 </div>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]292
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]293
294
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]295 <h2><a name="logical_operators"></a>Logical Operators</h2>
296 <div class="guidelineDetails">
297 <p>Use of <strong>||</strong> is discouraged as its clarity on some output devices is low (looking like the number 11 for instance).
298 <strong>&amp;&amp;</strong> is preferred over <strong>AND</strong> but either are acceptable, and a space should always precede and follow <strong>!</strong>.</p>
299<code><strong>INCORRECT</strong>:
300if ($foo || $bar)
301if ($foo AND $bar) // okay but not recommended for common syntax highlighting applications
302if (!$foo)
303if (! is_array($foo))
304
305<strong>CORRECT</strong>:
306if ($foo OR $bar)
307if ($foo && $bar) // recommended
308if ( ! $foo)
309if ( ! is_array($foo))
310</code>
311 </div>
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]312
313
314
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]315 <h2><a name="comparing_return_values_and_typecasting"></a>Comparing Return Values and Typecasting</h2>
316 <div class="guidelineDetails">
317 <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>
318 <p>Use the same stringency in returning and checking your own variables. Use <strong>===</strong> and <strong>!==</strong> as necessary.
319
320<code><strong>INCORRECT</strong>:
321// If 'foo' is at the beginning of the string, strpos will return a 0,
322// resulting in this conditional evaluating as TRUE
323if (strpos($str, 'foo') == FALSE)
324
325<strong>CORRECT</strong>:
326if (strpos($str, 'foo') === FALSE)
327</code>
328
329<code><strong>INCORRECT</strong>:
330function build_string($str = "")
331{
332 if ($str == "") // uh-oh! What if FALSE or the integer 0 is passed as an argument?
333 {
334
335 }
336}
337
338<strong>CORRECT</strong>:
339function build_string($str = "")
340{
341 if ($str === "")
342 {
343
344 }
345}</code>
346
347 <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>
348
349<code>$str = (string) $str; // cast $str as a string</code>
350
351 </div>
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]352
353
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]354 <h2><a name="debugging_code"></a>Debugging Code</h2>
355 <div class="guidelineDetails">
356 <p>No debugging code can be left in place for submitted add-ons unless it is commented out, i.e. no var_dump(), print_r(), die(), and exit() calls that were used while creating the add-on, unless they are commented out.</p>
357
358<code>// print_r($foo);</code>
359 </div>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]360
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]361
362
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]363 <h2><a name="whitespace_in_files"></a>Whitespace in Files</h2>
364 <div class="guidelineDetails">
Derek Allard5a8a4552009-08-17 18:06:30 +0000[diff] [blame]365 <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]366
367 <p><strong>INCORRECT</strong>:</p>
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]368<code>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]369&lt;?php
370 // ...there is whitespace and a linebreak above the opening PHP tag
371 // as well as whitespace after the closing PHP tag
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]372?&gt;
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]373</code>
374 <p><strong>CORRECT</strong>:</p>
375<code>&lt;?php
376 // this sample has no whitespace before or after the opening and closing PHP tags
377?&gt;</code>
378
379 </div>
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]380
381
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]382 <h2><a name="compatibility"></a>Compatibility</h2>
383 <div class="guidelineDetails">
384 <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>
385 </div>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]386
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]387
388
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]389 <h2><a name="class_and_file_names_using_common_words"></a>Class and File Names using Common Words</h2>
390 <div class="guidelineDetails">
391 <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>
392
393<code><strong>INCORRECT</strong>:
394class Email pi.email.php
395class Xml ext.xml.php
396class Import mod.import.php
397
398<strong>CORRECT</strong>:
399class Pre_email pi.pre_email.php
400class Pre_xml ext.pre_xml.php
401class Pre_import mod.pre_import.php
402</code>
403 </div>
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]404
405
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]406 <h2><a name="database_table_names"></a>Database Table Names</h2>
407 <div class="guidelineDetails">
Derek Allard5a8a4552009-08-17 18:06:30 +0000[diff] [blame]408 <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]409
410<code><strong>INCORRECT</strong>:
411email_addresses // missing both prefixes
412pre_email_addresses // missing exp_ prefix
413exp_email_addresses // missing unique prefix
414
415<strong>CORRECT</strong>:
416exp_pre_email_addresses
417</code>
418
419 <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>
420 </div>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]421
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]422
423
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]424 <h2><a name="one_file_per_class"></a>One File per Class</h2>
425 <div class="guidelineDetails">
Derek Allard5a8a4552009-08-17 18:06:30 +0000[diff] [blame]426 <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]427 </div>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]428
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]429
430
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]431 <h2><a name="whitespace"></a>Whitespace</h2>
432 <div class="guidelineDetails">
433 <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>
434 </div>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]435
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]436
437
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]438 <h2><a name="line_breaks"></a>Line Breaks</h2>
439 <div class="guidelineDetails">
440 <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>
441 </div>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]442
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]443
444
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]445 <h2><a name="code_indenting"></a>Code Indenting</h2>
446 <div class="guidelineDetails">
447 <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>
448
449<code><strong>INCORRECT</strong>:
450function foo($bar) {
451 // ...
452}
453
454foreach ($arr as $key => $val) {
455 // ...
456}
457
458if ($foo == $bar) {
459 // ...
460} else {
461 // ...
462}
463
464for ($i = 0; $i &lt; 10; $i++)
465 {
466 for ($j = 0; $j &lt; 10; $j++)
467 {
468 // ...
469 }
470 }
471
472<strong>CORRECT</strong>:
473function foo($bar)
474{
475 // ...
476}
477
478foreach ($arr as $key => $val)
479{
480 // ...
481}
482
483if ($foo == $bar)
484{
485 // ...
486}
487else
488{
489 // ...
490}
491
492for ($i = 0; $i &lt; 10; $i++)
493{
494 for ($j = 0; $j &lt; 10; $j++)
495 {
496 // ...
497 }
498}</code>
499 </div>
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]500
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]501
502 <h2><a name="bracket_spacing"></a>Bracket and Parenthetic Spacing</h2>
503 <div class="guidelineDetails">
504 <p>In general, parenthesis and brackets should not use any additional spaces. The exception is that a space should always follow PHP control structures that accept arguments with parenthesis (declare, do-while, elseif, for, foreach, if, switch, while), to help distinguish them from functions and increase readability.</p>
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]505
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]506<code>INCORRECT:
507$arr[ $foo ] = 'foo';
508
509CORRECT:
510$arr[$foo] = 'foo'; // no spaces around array keys
511
512
513INCORRECT:
514function foo ( $bar )
515{
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]516
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]517}
518
519CORRECT:
520function foo($bar) // no spaces around parenthesis in function declarations
521{
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]522
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]523}
524
525
526INCORRECT:
527foreach( $query->result() as $row )
528
529CORRECT:
530foreach ($query->result() as $row) // single space following PHP control structures, but not in interior parenthesis
531</code>
532 </div>
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]533
534
535
Derek Allard2f304d62010-07-05 07:40:26 -0400[diff] [blame]536 <h2><a name="localized_text"></a>Localized Text</h2>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]537 <div class="guidelineDetails">
Derek Allard2f304d62010-07-05 07:40:26 -0400[diff] [blame]538 <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]539
540<code>INCORRECT:
541return "Invalid Selection";
542
543CORRECT:
Derek Allard2f304d62010-07-05 07:40:26 -0400[diff] [blame]544return $this->lang->line('invalid_selection');</code>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]545 </div>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]546
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]547
548
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]549 <h2><a name="private_methods_and_variables"></a>Private Methods and Variables</h2>
550 <div class="guidelineDetails">
551 <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>
552
553<code>convert_text() // public method
554_convert_text() // private method</code>
555 </div>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]556
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]557
558
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]559 <h2><a name="php_errors"></a>PHP Errors</h2>
560 <div class="guidelineDetails">
561 <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>
562
563 <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>
564
565<code>if (ini_get('display_errors') == 1)
566{
567 exit "Enabled";
568}</code>
569
570 <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>
571
572<code>ini_set('display_errors', 1);</code>
573
574 <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>
575 </div>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]576
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]577
578
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]579 <h2><a name="short_open_tags"></a>Short Open Tags</h2>
580 <div class="guidelineDetails">
581 <p>Always use full PHP opening tags, in case a server does not have short_open_tag enabled.</p>
582
583<code><strong>INCORRECT</strong>:
584&lt;? echo $foo; ?&gt;
585
586&lt;?=$foo?&gt;
587
588<strong>CORRECT</strong>:
589&lt;?php echo $foo; ?&gt;</code>
590 </div>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]591
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]592
593
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]594 <h2><a name="one_statement_per_line"></a>One Statement Per Line</h2>
595 <div class="guidelineDetails">
596 <p>Never combine statements on one line.</p>
597
598<code><strong>INCORRECT</strong>:
599$foo = 'this'; $bar = 'that'; $bat = str_replace($foo, $bar, $bag);
600
601<strong>CORRECT</strong>:
602$foo = 'this';
603$bar = 'that';
604$bat = str_replace($foo, $bar, $bag);
605</code>
606 </div>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]607
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]608
609
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]610 <h2><a name="strings"></a>Strings</h2>
611 <div class="guidelineDetails">
612 <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>
613
614<code><strong>INCORRECT</strong>:
615"My String" // no variable parsing, so no use for double quotes
616"My string $foo" // needs braces
617'SELECT foo FROM bar WHERE baz = \'bag\'' // ugly
618
619<strong>CORRECT</strong>:
620'My String'
621"My string {$foo}"
622"SELECT foo FROM bar WHERE baz = 'bag'"</code>
623 </div>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]624
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]625
626
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]627 <h2><a name="sql_queries"></a>SQL Queries</h2>
628 <div class="guidelineDetails">
629 <p>MySQL keywords are always capitalized: SELECT, INSERT, UPDATE, WHERE, AS, JOIN, ON, IN, etc.</p>
630
631 <p>Break up long queries into multiple lines for legibility, preferably breaking for each clause.</p>
632
633<code><strong>INCORRECT</strong>:
634// keywords are lowercase and query is too long for
635// a single line (... indicates continuation of line)
636$query = $this->db->query("select foo, bar, baz, foofoo, foobar as raboof, foobaz from exp_pre_email_addresses
637...where foo != 'oof' and baz != 'zab' order by foobaz limit 5, 100");
638
639<strong>CORRECT</strong>:
640$query = $this->db->query("SELECT foo, bar, baz, foofoo, foobar AS raboof, foobaz
641 FROM exp_pre_email_addresses
642 WHERE foo != 'oof'
643 AND baz != 'zab'
644 ORDER BY foobaz
645 LIMIT 5, 100");</code>
646 </div>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]647
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]648
649
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]650 <h2><a name="default_function_arguments"></a>Default Function Arguments</h2>
651 <div class="guidelineDetails">
652 <p>Whenever appropriate, provide function argument defaults, which helps prevent PHP errors with mistaken calls and provides common fallback values which can save a few lines of code. Example:</p>
653
654<code>function foo($bar = '', $baz = FALSE)</code>
655 </div>
Barry Mienydd671972010-10-04 16:33:58 +0200[diff] [blame]656
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]657
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]658
659</div>
660
661
662
663</div>
664<!-- END CONTENT -->
665
666
667<div id="footer">
668<p>
669Previous Topic:&nbsp;&nbsp;<a href="security.html">Security</a>
670&nbsp;&nbsp;&nbsp;&middot;&nbsp;&nbsp;
671<a href="#top">Top of Page</a>&nbsp;&nbsp;&nbsp;&middot;&nbsp;&nbsp;
672<a href="../index.html">User Guide Home</a>&nbsp;&nbsp;&nbsp;&middot;&nbsp;&nbsp;
673Next Topic:&nbsp;&nbsp;<a href="../doc_style/index.html">Writing Documentation</a>
674</p>
Derek Jones898949f2011-01-28 07:42:16 -0600[diff] [blame]675<p><a href="http://codeigniter.com">CodeIgniter</a> &nbsp;&middot;&nbsp; Copyright &#169; 2006 - 2011 &nbsp;&middot;&nbsp; <a href="http://ellislab.com/">EllisLab, Inc.</a></p>
Derek Allard2067d1a2008-11-13 22:59:24 +0000[diff] [blame]676</div>
677
678</body>
Rick Ellis5a9fd7a2008-08-31 05:58:32 +0000[diff] [blame]679</html>