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* PHP File Formatting
* Inline Documentation
* Naming Conventions
* Coding Style
* Inline Documentation
* Errors and Exceptions
* Appendix: Automatted tests
* CodeSniffer Testbed

h2. Goals
Use an indent of 4 spaces with no tab characters. Editors should be configured to treat tabs as spaces in order to prevent injection of tab characters into the source code.

The code following a opening brace must be indented 4 additional spaces.

{code}
if ($x == 1) {
$indented_code = 1;
if ($new_line == 1) {
$more_indented_code = 1;
}
}
{code}

Multiple assignments must have the same indentation.

Lines should not contain trailing spaces. In order to facilitate this convention, most editors can be configured to strip trailing spaces, such as upon a save operation.

h1. Naming Conventions

h2. Abstractions Used in API (Class Interfaces)

When creating an API for use by application developers (as opposed to Zend Framework internal developers), if application developers must identify abstractions using a compound name, separate the names using underscores, not camelCase. For example, the name used for the MySQL PDO driver is 'pdo_mysql', not 'pdoMysql'. When the developer uses a string, normalize it to lowercase. Where reasonable, add constants to support this (e.g. PDO_MYSQL).

h2. Classes

The Zend Framework employs a class naming convention whereby the names of the classes directly map to the directories in which they are stored. The root level directory of the Zend Framework is the "{{Zend/}}" directory, under which all classes are stored hierarchically.

Class names may only contain alphanumeric characters. Numbers are permitted in class names but are discouraged. Underscores are only permitted in place of the path separator. For example, the filename "{{Zend/Db/Table.php}}" must map to the class name "{{Zend_Db_Table}}".

If a class name is comprised of more than one word, the first letter of each new word must be capitalized. Successive capitalized letters are not allowed; e.g., a class "{{Zend_PDF}}" is not allowed, while "{{Zend_Pdf}}" is acceptable.

Zend Framework classes that are authored by Zend or one of the participating partner companies and distributed with the Framework must always start with "{{Zend_}}" and must be stored under the "{{Zend/}}" directory hierarchy accordingly.

These are examples of acceptable names for classes:

{code}
Zend_Db

Zend_View

Zend_View_Helper
{code}

{note:title=Important}
Code that operates with the framework but is not part of the framework, such as code written by a framework end-user and not Zend or one of the framework's partner companies, must never start with "{{Zend_}}".
{note}

h2. Interfaces

Interface classes must follow the same conventions as other classes (see above), but must end with "{{_Interface}}", such as in these examples:

{code}
Zend_Log_Adapter_Interface

Zend_Controller_Dispatcher_Interface
{code}

h2. Filenames

For all other files, only alphanumeric characters, underscores, and the dash character ("{{-}}") are permitted. Spaces are prohibited.

Any file that contains any PHP code must end with the extension "{{.php}}". These examples show the acceptable filenames for containing the class names from the examples in the section above:

{code}
Zend/Db.php

Zend/Controller/Front.php

Zend/View/Helper/FormRadio.php
{code}

File names must follow the mapping to class names described above.

h2. Functions and Methods

Function names may only contain alphanumeric characters. Underscores are not permitted. Numbers are not allowed in function names.

Function names must always start with a lowercase letter. When a function name consists of more than one word, the first letter of each new word must be capitalized. This is commonly called the "camelCaps" method.

Verbosity is encouraged. Function names should be as illustrative as is practical to enhance understanding.

These are examples of acceptable names for functions:

{code}
filterInput()

getElementById()

widgetFactory()
{code}

For object-oriented programming, accessors for object members should always be prefixed with either "{{get}}" or "{{set}}". When using design patterns, such as the Singleton or Factory patterns, the name of the method should contain the pattern name where practical to make the pattern more readily recognizable.

Though function names may not contain the underscore character, class methods that are declared as {{protected}} or {{private}} must begin with a single underscore, as in the following example:

{code}
class Zend_Foo
{
protected function _fooBar()
{
// ...
}
}
{code}

Functions in the global scope, or "floating functions," are permitted but heavily discouraged. It is recommended that these functions be wrapped in a class and declared static.

Functions or variables declared with a "static" scope in a class generally should not be "private", but protected instead. Use "final" if the function should not be extended.

The opening brace of functions and methods has to be in the next line.

{code}
function Myfunction($parameter1)
{
}
{code}

h3. Optional Parameters

Use "null" as the default value instead of "false", for situations like this:

public function foo($required, $optional = null)

*when* $optional does not have or need a particular default value.

However, if an optional parameter is boolean, and its logical default value should be true, or false, then using true or false is acceptable.

h2. Variables

Variable names may only contain alphanumeric characters. Underscores or numbers are not permitted.

For class member variables that are declared with the {{private}} or {{protected}} construct, the first character of the variable name must be a single underscore. This is the only acceptable usage of an underscore in a variable name. Member variables declared as "public" may never start with an underscore. For example:

{code}
class Zend_Foo
{
protected $_bar;
}
{code}

Like function names, variable names must always start with a lowercase letter and follow the "camelCaps" capitalization convention.

Verbosity is encouraged. Variable names should always be as verbose as practical. Terse variable names such as "{{$i}}" and "{{$n}}" are discouraged for anything other than the smallest loop contexts. If a loop contains more than 20 lines of code, variables for such indices or counters need to have more descriptive names.

h2. Constants

Constants may contain both alphanumeric characters and the underscore. Numbers are permitted in constant names.

Constant names must always have all letters capitalized.

To enhance readability, words in constant names must be separated by underscore characters. For example, "{{EMBED_SUPPRESS_EMBED_EXCEPTION}}" is permitted but "{{EMBED_SUPPRESSEMBEDEXCEPTION}}" is not.

Constants must be defined as class members by using the "const" construct. Defining constants in the global scope with "define" is permitted but heavily discouraged.

h2. Booleans and the NULL Value

Unlike PHP's documentation, the Zend Framework uses lowercase for both boolean values and the "{{null}}" value.

h1. Coding style

h2. PHP Code Demarcation

PHP code must always be delimited by the full-form, standard PHP tags (although you should see the note about [the closing PHP tag|#General]):

{code}
<?php

?>
{code}

Short tags are only allowed within view scripts.

h2. Strings

h3. String Literals

When a string is literal (contains no variable substitutions), the apostrophe or "single quote" must always used to demarcate the string:

{code}
$a = 'Example String';
{code}

h3. String Literals Containing Apostrophes

When a literal string itself contains apostrophes, it is permitted to demarcate the string with quotation marks or "double quotes". This is especially encouraged for SQL statements:

{code}
$sql = "SELECT `id`, `name` from `people` WHERE `name`='Fred' OR `name`='Susan'";
{code}

The above syntax is preferred over escaping apostrophes.

h3. Variable Substitution

Variable substitution is permitted using either of these two forms:

{code}
$greeting = "Hello $name, welcome back!";

$greeting = "Hello {$name}, welcome back!";
{code}

For consistency, this form is not permitted:

{code}
$greeting = "Hello ${name}, welcome back!";
{code}

h3. String Concatenation

Strings may be concatenated using the "{{.}}" operator. A space must always be added before and after the "{{.}}" operator to improve readability:

{code}
$company = 'Zend' . 'Technologies';
{code}

When concatenating strings with the "{{.}}" operator, it is permitted to break the statement into multiple lines to improve readability. In these cases, each successive line should be padded with whitespace such that the "{{.}}" operator is aligned under the "{{=}}" operator:

{code}
$sql = "SELECT `id`, `name` FROM `people` "
. "WHERE `name` = 'Susan' "
. "ORDER BY `name` ASC ";
{code}

h2. Arrays

h3. Numerically Indexed Arrays

Negative numbers are not permitted as array indices.

An indexed array may be started with any non-negative number, however this is discouraged and it is recommended that all arrays have a base index of {{0}}.

When declaring indexed arrays with the {{array}} construct, a trailing space must be added after each comma delimiter to improve readability:

{code}
$sampleArray = array(1, 2, 3, 'Zend', 'Studio');
{code}

It is also permitted to declare multi-line indexed arrays using the {{array}} construct. In this case, each successive line must be padded with spaces such that beginning of each line and each value aligns as shown below:

{code}
$sampleArray = array(1, 2, 3, 'Zend',
'Studio', $a, $b, $c,
56.44, $d, 500);
{code}

h3. Associative Arrays

When declaring associative arrays with the {{array}} construct, it is encouraged to break the statement into multiple lines. In this case, each successive line must be padded with whitespace such that both the keys and the values are aligned:

{code}
$sampleArray = array('firstKey' => 'firstValue',
'secondKey' => 'secondValue');
{code}

h2. Classes

h3. Class Declarations

Classes must be named by following the naming conventions.

The brace is always written on the line underneath the class name ("one true brace" form).

Every class must have a documentation block that conforms to the phpDocumentor standard.

Any code within a class must be indented the standard indent of four spaces.

Only one class is permitted per PHP file.

Placing additional code in a class file is permitted but heavily discouraged. In these files, a blank line must separate the class from any additional PHP code in the file.

This is an example of an acceptable class declaration:

{code}
/**
* Class Docblock Here
*/
class Zend_Class
{
// entire content of class
// must be indented four spaces
}
{code}

h3. Class Member Variables

Member variables must be named by following the variable naming conventions.

Any variables declared in a class must be listed at the top of the class, prior to declaring any functions.

The {{var}} construct is not permitted. Member variables always declare their visibility by using one of the {{private}}, {{protected}}, or {{public}} constructs. Accessing member variables directly by making them public is permitted but discouraged in favor of accessor methods having the {{set}} and {{get}} prefixes.

h2. Functions and Methods

h3. Function and Method Declaration

Functions and class methods must be named by following the naming conventions.

Methods must always declare their visibility by using one of the {{private}}, {{protected}}, or {{public}} constructs.

Following the more common usage in the PHP developer community, static methods should declare their visibility first:
{code}
public static foo() { ... }
private static bar() { ... }
protected static goo() { ... }
{code}

As for classes, the opening brace for a function or method is always written on the line underneath the function or method name ("one true brace" form). There is no space between the function or method name and the opening parenthesis for the arguments.

This is an example of acceptable class method declarations:

{code}
/**
* Class Docblock Here
*/
class Zend_Foo
{
/**
* Method Docblock Here
*/
public function sampleMethod($a)
{
// entire content of function
// must be indented four spaces
}

/**
* Method Docblock Here
*/
protected function _anotherMethod()
{
// ...
}
}
{code}

{info:title=Please note}
Passing function or method arguments by reference is only permitted by defining the reference in the function or method declaration, as in the following example:

{code}
function sampleMethod(&$a)
{}
{code}

Call-time pass by-reference is prohibited.
{info}

The return value must not be enclosed in parentheses. This can hinder readability and can also break code if a function or method is later changed to return by reference.

{code}
function foo()
{
// WRONG
return($this->bar);

// RIGHT
return $this->bar;
}
{code}

The use of [type hinting|http://php.net/manual/en/language.oop5.typehinting.php] is encouraged where possible with respect to the component design. For example,

{code}
class Zend_Component
{
public function foo(SomeInterface $object)
{}

public function bar(array $options)
{}
}
{code}

Where possible, try to keep your use of exceptions vs. type hinting consistent, and not mix both approaches at the same time in the same method for validating argument types. However, before PHP 5.2, "Failing to satisfy the type hint results in a fatal error," and might fail to satisfy other coding standards involving the use of throwing exceptions. Beginning with PHP 5.2, failing to satisfy the type hint results in an E_RECOVERABLE_ERROR, requiring developers to deal with these from within a custom error handler, instead of using a try..catch block.

h3. Function and Method Usage

Function arguments are separated by a single trailing space after the comma delimiter. This is an example of an acceptable function call for a function that takes three arguments:

{code}
threeArguments(1, 2, 3);
{code}

Call-time pass by-reference is prohibited. Arguments to be passed by reference must be defined in the function declaration.

For functions whose arguments permit arrays, the function call may include the "array" construct and can be split into multiple lines to improve readability. In these cases, the standards for writing arrays still apply:

{code}
threeArguments(array(1, 2, 3), 2, 3);

threeArguments(array(1, 2, 3, 'Zend',
'Studio', $a, $b, $c,
56.44, $d, 500), 2, 3);
{code}

h2. Control Statements

h3. If / Else / Elseif

Control statements based on the "{{if}}", "{{else}}", and "{{elseif}}" constructs must have a single space before the opening parenthesis of the conditional, and a single space between the closing parenthesis and opening brace.

Within the conditional statements between the parentheses, operators must be separated by spaces for readability. Inner parentheses are encouraged to improve logical grouping of larger conditionals.

The opening brace is written on the same line as the conditional statement. The closing brace is always written on its own line. Any content within the braces must be indented four spaces.

{code}
if ($a != 2) {
$a = 2;
}
{code}

For "{{if}}" statements that include "{{elseif}}" or "{{else}}", the formatting must be as in these examples:

{code}
if ($a != 2) {
$a = 2;
} else {
$a = 7;
}


if ($a != 2) {
$a = 2;
} else if ($a == 3) {
$a = 4;
} else {
$a = 7;
}
{code}

PHP allows for these statements to be written without braces in some circumstances. The coding standard makes no differentiation and all "{{if}}", "{{elseif}}", or "{{else}}" statements must use braces.

Use of the "{{elseif}}" construct is not allowed in favor of the "{{else if}}" combination.

h3. Switch

Control statements written with the "{{switch}}" construct must have a single space before the opening parenthesis of the conditional statement, and also a single space between the closing parenthesis and the opening brace.

All content within the "{{switch}}" statement must be indented four spaces. Content under each "{{case}}" statement must be indented an additional four spaces.

{code}
switch ($numPeople) {
case 1:
break;

case 2:
break;

default:
break;
}
{code}

The construct "{{default}}" may never be omitted from a "{{switch}}" statement.

{info:title=Please note}
It is sometimes useful to write a "{{case}}" statement which falls through to the next case by not including a "{{break}}" or "{{return}}". To distinguish these cases from bugs, such "{{case}}" statements must contain the comment "{{// break intentionally omitted}}".
{info}

h2. Global

Usage of the *global* keyword is not allowed. Use $GLOBALS[xxx] instead.

h1. Inline Documentation

h2. General

All docblock parts are compatible with the phpDocumentor format and must follow the following standard.
Docblocks start always with {{/**}}. The use of {{/*}} or {{//}} is only allowed for comments within functions.

A docblock must contain a short description and minimum one parameter.

{code}
/**
* SHORT_DESCRIPTION
*
* @param
*/
{code}

Optionally a long description and multiple parameters can be added.

{code}
/**
* SHORT_DESCRIPTION
*
* LONG_DESCRIPTION
* SPANS MULTIPLE
* LINES
*
* @param
* @param
*/
{code}

h2. Indenting

/**
* blablabla
*
* @component All descriptive parts
* @uses have the same indenting
{code}

Also when describing parameters the keywords, parameters, and description have to have the same indenting to be under each other.

{code}
/**
* blablabla
*
* @param string $value Description of this value
* @param integer $othervalue Another description
* to license@zend.com so we can send you a copy immediately.
*
* @category Zend
* @package __COMPONENT__ __PACKAGENAME__
* @subpackage __SEPARATION__
* @subpackage __SUBPACKAGENAME__
* @copyright Copyright (c) 2005-__ENDDATE__ Zend Technologies USA Inc. (http://www.zend.com)
* @license http://framework.zend.com/license/new-bsd New BSD License
* @version $Id: $
* @depreciated Since 0.0.1
*/
{code}

When other filestypes are used like *.SH, *.BAT, *.JS and so on, the header block must also be contained as header comment. Only when a filetype does not support comments like *.CSS the header block can be omited. The clauses must be added in the above seen order.

__COMPONENT__ The {{@package}} clause has to be the component which this file is part of it, for example Zend_Db or Zend_Gdata. There are only two exceptions:
All demo files are located in the component *Demos* and all classes in the incubator have to be handled as if they are in core... so "incubator/Zend/Class" becomes the component "Zend_Class".
There must exist exact one {{@package}} clause per header.

__SEPARATION__ The {{@subpackage}} clause has to be a logical separation within this component. Logical separations occur when there are several directories which seperate parts of the same component. The component name if contained in the separation has to be omitted. For example a file which is in Zend/Db/Adapters/* will have *Adapters* as separation and *Zend_Db* as component. Only files which are in the main directory of the framework which is "Zend" can omit the subpackage. There must exist maximum one {{@subpackage}} clause per header.

__ENDDATE__ has to be the actual year of the release of the framework.
The {{@copyright}} clause has to include the actual year of the release of the framework.

If this file contains a depreciated class it must have the optional {{@depreciated}} clause.

h2. Require Once

{code}

This clause has also to be added when a require_once is in the code and not in the file header.
h2. Class/Interface Header

{code}
if (!$allStrings) {
/**
* @see Zend_Controller_Dispatcher_Exception
*/
require_once 'Zend/Controller/Dispatcher/Exception.php';
throw new Zend_Controller_Dispatcher_Exception('Exception text');
}
{code}
A class or interface must have a class header looking like this:

h2. Class Header

A class must have a class header looking like this:

{code}
/**
* Description of the class
*
* More descriptive text which
* is allowed to span multiple lines
*
* @category Zend
* @package __COMPONENT__ __PACKAGE__
* @subpackage __SEPARATION__
* @subpackage __SUBPACKAGE__
* @uses __USES__
* @see __SEE__
* @since __SINCE__
* @copyright Copyright (c) 2005-__ENDDATE__ Zend Technologies USA Inc. (http://www.zend.com)
* @license http://framework.zend.com/license/new-bsd New BSD License
* @depreciated Since 0.0.1
*/
class Zend_Controller_Dispatcher extends Zend_Controller_Dispatcher_Class implements Zend_Controller_Dispatcher_Interface
{code}

The discription explains what this class does.
The clauses must be added in the above seen order.

__COMPONENT__ has to be the component which this file is part of it, for example Zend_Db or Zend_Gdata.
The short discription explains what this class does. It must not extend one single line.

__SEPARATION__ has to be a logical separation within this component. Logical separations occur when there are several directories which seperate parts of the same component. For example a file which is in Zend/Db/Adapters/* will have "Zend_Db_Adapters" as separation. There is only one exception: All files which are part of the demos directory have to be in the Demos subpackage. Only files which are in the main directory of the framework which is "Zend" can omit the subpackage.
The long descriptive text can be ommitted if there is no need for it.

__USES__ has to be the extended or implemented classname. A class which "extends Zend_MyClass" must have a clause @uses Zend_MyClass. Also a class which "implementes Zend_MyClass" must have a clause @uses Zend_MyClass.
The {{@package}} clause has to contain the component which this file is part of it, for example Zend_Db or Zend_Gdata.

__ENDDATE__ has to be the actual year of the release of the framework.
The {{@subpackage}} clause has to contain a logical separation within this component. Logical separations occur when there are several directories which seperate parts of the same component. For example a file which is in Zend/Db/Adapters/* will have "Zend_Db_Adapters" as separation. There is only one exception: All files which are part of the demos directory have to be in the Demos subpackage. Only files which are in the main directory of the framework which is "Zend" can omit the subpackage.

The {{@uses}} clause has to contain the extended or implemented classname. A class which "extends Zend_MyClass" must have a clause @uses Zend_MyClass. Also a class which "implementes Zend_MyClass" must have a clause @uses Zend_MyClass. When multiple classes or interfaces are used, you must include a @uses clause for every class or interface. When no class is extended or interface is implemented then the @uses clause must be ommitted.

The {{@see}} clause is optional and can be added to link to another component within the framework. You can add multiple clauses.

The {{@since}} clause can be added optionally to include the version since which this class is available. It must include the complete version number of the framework. Only one since clause is allowed to be added.

The {{@copyright}} clause has to include the actual year of the release of the framework.

If this file contains a depreciated class it must have the optional {{@depreciated}} clause in the same format as the {{@since}} clause.

h2. Function Header

* @param array $rest Rest array possible values
* Some additional description
* @param array|null $config (optional) Optional My optional value
* @param Zend_Control $control (optional) xxx
* @since Version 1.2.3
* @see Zend_Anything
* @throws Zend_Config_Exception When value is true
* @return array
*/
* string
* array
* Zend_xxx (must be an existing class of the framework)
* false
* true
If a parameter can be omitted the description must prepend a *(optional)* like shown above.

A {{@since}} clause can be added to show since when this function is available. Only one clause is allowed.

The {{@see}} clause can be added to link to another component which describes functionallity of this method, or which is used by this method. Multiple clauses are allowed. Every clause must contain only one class link.

If the function can throw an exception the *@throws* clause must be declared.
Multiple exception types must be seperated with *"|"*. Also a description must be added why the exception is thrown.

A *@return* clause must always be defined. Only for class constructor and destructor the @return clause must be ommitted.
If multiple types can be returned the types must be seperated with *"|"*.
An description can be appended, but is not necessary.
If the class itself is returned (fluid interface) then the description
{code}
* @return Zend_Class *Provides a fluid interface*
{code}
must be added.

If the function does not return any value then the return value must be set to *null* *void*
{code}
* @return null void
{code}

{note:title=Hint}
There has been discussions in past about void versus null. Keep in mind that these two are not the same. Null means that a empty variable is returned. But void means that nothing is returned. This is a small but important difference. Therefor when return is even not called, void has to be declared in the function docblock.
{note}

h2. Inline Documentation

Documentation within a method is good practice and should be done to increase readability of the code.

The only acceptable syntax is phpdoc ("{{/**}}") or pearl ("{{//}}").
The usage of the ("{{#}}") or the ("{{/**}}") Syntax is not allowed.

h1. Naming Conventions
h1. Errors and Exceptions

h2. Abstractions Used in API (Class Interfaces)
The Zend Framework codebase must be {{E_STRICT}} compliant. Zend Framework code should not emit PHP warning (E_WARNING, E_USER_WARNING), notice (E_NOTICE, E_USER_NOTICE), or strict (E_STRICT) messages when {{error_reporting}} is set to {{E_ALL | E_STRICT.}}

When creating an API for use by application developers (as opposed to Zend Framework internal developers), if application developers must identify abstractions using a compound name, separate the names using underscores, not camelCase. For example, the name used for the MySQL PDO driver is 'pdo_mysql', not 'pdoMysql'. When the developer uses a string, normalize it to lowercase. Where reasonable, add constants to support this (e.g. PDO_MYSQL).
See http://www.php.net/errorfunc for information on {{E_STRICT}}.

h2. Classes
Zend Framework code should not emit PHP errors, if it is reasonably possible. Instead, throw meaningful exceptions. Zend Framework components have {{Exception}} class derivatives specifically for this purpose:

The Zend Framework employs a class naming convention whereby the names of the classes directly map to the directories in which they are stored. The root level directory of the Zend Framework is the "{{Zend/}}" directory, under which all classes are stored hierarchically.

Class names may only contain alphanumeric characters. Numbers are permitted in class names but are discouraged. Underscores are only permitted in place of the path separator. For example, the filename "{{Zend/Db/Table.php}}" must map to the class name "{{Zend_Db_Table}}".

If a class name is comprised of more than one word, the first letter of each new word must be capitalized. Successive capitalized letters are not allowed; e.g., a class "{{Zend_PDF}}" is not allowed, while "{{Zend_Pdf}}" is acceptable.

Zend Framework classes that are authored by Zend or one of the participating partner companies and distributed with the Framework must always start with "{{Zend_}}" and must be stored under the "{{Zend/}}" directory hierarchy accordingly.

These are examples of acceptable names for classes:

{code}
class Zend_Exception extends Exception
Zend_Db {}

class Zend_Component_Exception extends Zend_Exception
Zend_View {}

class Zend_Component_SpecificException extends Zend_Component_Exception
Zend_View_Helper {}
{code}

{note:title=Important}
Code that operates with the framework but is not part of the framework, such as code written by a framework end-user and not Zend or one of the framework's partner companies, must never start with "{{Zend_}}".
{note}
It is considered best practice within framework component code that exceptions are instantiated through the traditional {{new}} constructor method.

h2. Interfaces

Interface classes must follow the same conventions as other classes (see above), but must end with "{{_Interface}}", such as in these examples:

{code}
Zend_Log_Adapter_Interface
require_once 'Zend_Component_SpecificException.php';

Zend_Controller_Dispatcher_Interface
{code}

h2. Filenames

For all other files, only alphanumeric characters, underscores, and the dash character ("{{-}}") are permitted. Spaces are prohibited.

Any file that contains any PHP code must end with the extension "{{.php}}". These examples show the acceptable filenames for containing the class names from the examples in the section above:

{code}
Zend/Db.php

Zend/Controller/Front.php

Zend/View/Helper/FormRadio.php
{code}

File names must follow the mapping to class names described above.

h2. Functions and Methods

Function names may only contain alphanumeric characters. Underscores are not permitted. Numbers are permitted in function names but are discouraged.

Function names must always start with a lowercase letter. When a function name consists of more than one word, the first letter of each new word must be capitalized. This is commonly called the "camelCaps" method.

Verbosity is encouraged. Function names should be as illustrative as is practical to enhance understanding.

These are examples of acceptable names for functions:

{code}
filterInput()

getElementById()

widgetFactory()
{code}

For object-oriented programming, accessors for object members should always be prefixed with either "{{get}}" or "{{set}}". When using design patterns, such as the Singleton or Factory patterns, the name of the method should contain the pattern name where practical to make the pattern more readily recognizable.

Though function names may not contain the underscore character, class methods that are declared as {{protected}} or {{private}} must begin with a single underscore, as in the following example:

{code}
class Zend_Foo Zend_Component
{
protected function _fooBar()
public function foo($condition)
{
if ($condition) {
throw new Zend_Component_SpecificException(
'Some meaningful exception message');
// ... }
}
}
{code}

Functions in the global scope, or "floating functions," are permitted but discouraged. It is recommended that these functions be wrapped in a class and declared static.

Functions or variables declared with a "static" scope in a class generally should not be "private", but protected instead. Use "final" if the function should not be extended.

The opening brace of functions and methods has to be in the next line.

Exceptions must be lazy loaded before they are thrown:
{code}
function Myfunction($parameter1)
{
if ($condition) {
require_once 'Zend_Component_SpecificException.php';
throw new Zend_Component_SpecificException(
'Some meaningful exception message');
}
{code}

h3. Optional Parameters
Reasonable care should be taken to avoid throwing exceptions except when genuinely appropriate. In general, if a Zend Framework component is asked to perform a duty that it cannot perform in a certain situation (e.g., illegal input, cannot read requested file), then throwing an exception is a sensible course of action. Conversely, if a component is able to perform its requested duty, despite some variance from expected input, then the component should continue with its work, rather than throw an exception.

Use "null" as the default value instead of "false", for situations like this:
h2. Exception best practices

public function foo($required, $optional = null)
* Use specific derived exceptions in both {{throw}} and {{catch}}. See the following two items:

*when* $optional does not have or need a particular default value.
* Avoid throwing the {{Exception}} base class, or other exception superclass. The more specific the exception, the better it communicates to the user what happened.

However, if an optional parameter is boolean, and its logical default value should be true, or false, then using true or false is acceptable.
* Avoid catching the {{Exception}} base class, or other exception superclass. If a {{try}} block might encounter more than one type of exception, write a separate {{catch}} block for each specific exception, not one {{catch}} block for an exception superclass.

h2. Variables
* Some classes may require you to write more than one derived exception class. Write as many exception classes as needed, to distinguish between different types of situations. For example, "_invalid argument value_" is different from, "_you don't have a needed privilege_." Create different exceptions to identify different cases.

Variable names may only contain alphanumeric characters. Underscores are not permitted. Numbers are permitted in variable names but are discouraged.
* Don't put important diagnostic information only in the text of the exception method. Create methods and members in derived exception classes as needed, to provide information to the {{catch}} block. Create an exception constructor method that takes appropriate arguments, and populate the members of the class with those arguments.

For class member variables that are declared with the {{private}} or {{protected}} construct, the first character of the variable name must be a single underscore. This is the only acceptable usage of an underscore in a variable name. Member variables declared as "public" may never start with an underscore. For example:
* Don't silently suppress exceptions and allow execution to continue in an erroneous state. If you catch an exception, either correct the condition or throw a new exception.

{code}
class Zend_Foo
{
protected $_bar;
}
{code}
* Keep implementation-specific exceptions isolated to the appropriate layer of your application. For instance, don't propagate {{SQLException}} out of the data layer code and into business layer code.

Like function names, variable names must always start with a lowercase letter and follow the "camelCaps" capitalization convention.
* Don't use exceptions as a mechanism of flow control, or to return valid return values from a function.

Verbosity is encouraged. Variable names should always be as verbose as practical. Terse variable names such as "{{$i}}" and "{{$n}}" are discouraged for anything other than the smallest loop contexts. If a loop contains more than 20 lines of code, variables for such indices or counters need to have more descriptive names.
* Clean up resources such as database connections or network connections. PHP does not support a {{finally}} block as some programming languages do, so either clean up in the {{catch}} blocks, or else design flow control outside the {{catch}} block to perform cleanup, and let execution continue after the {{catch}}.

h2. Constants
* Use documentation from other languages for other best practices regarding using exceptions. Many of the principles are applicable, regardless of the language.

Constants may contain both alphanumeric characters and the underscore. Numbers are permitted in constant names.
h1. CodeSniffer Testbed

Constant names must always have all letters capitalized.
The complete framework is tested with a coding standard which we have written using PHP_CodeSniffer. Several existing tests have been reused and others have been rewritten to allow automatic testing of the above written coding standard.
In some points the CodeSniffer tests are more restrictive than the written standard to make the code more readable and consistent.

To enhance readability, words in constant names must be separated by underscore characters. For example, "{{EMBED_SUPPRESS_EMBED_EXCEPTION}}" is permitted but "{{EMBED_SUPPRESSEMBEDEXCEPTION}}" is not.

Constants must be defined as class members by using the "const" construct. Defining constants in the global scope with "define" is permitted but discouraged.

h2. Booleans and the NULL Value

Unlike PHP's documentation, the Zend Framework uses lowercase for both boolean values and the "{{null}}" value.

h1. Coding style

h2. Global

Usage of the *global* keyword is not allowed. Use $GLOBALS[xxx] instead.

h1. Appendix: Automatted tests

Actually we are writing automatted tests for Zend Framework. All tests are in sum a defined coding standard for Zend Framework using PHP_CodeSniffer and will be delivered with Zend Framework in the future. What has been done until now can be found in the trunk -> incubator -> tools -> codingstandard.

Feel free to mention tests that should be added...
{toc-zone}