PSR-2：代码风格指导

代码风格指导

这个指导继承并扩展基本代码规范[PSR-1](https://github.com/php-fig/fig-

一、概览

• 代码必须遵循一个代码风格指导基本规范[PSR-1]。

• 代码必须使用4个空格缩进，而不是使用tab。

• 行长度一定不能有硬限制；软限制一定是120个字符；每行应该不超过80个字符。

• 在声明namespace后一定有一个空行，在声明完所有的use后也必须有一个空行。

• 类的左花括号一定在下一行，右花括号也一定在类内容的下一行。

• 方法的左花括号一定在方法名的下一行，右花括号一定在方法体的下一行。

• 所有的属性和方法一定要定义可见性；abstract和final必须在可见性之前定义；static一定在可见性之后定义。

• 控制结构关键词之后一定有一个空格；方法和函数名之后一定不能有空格。

• 控制结构的左花括号一定与关键词在同一行，右花括号一定在内容的下一行。

• 控制结构的左圆括号之后一定不能有空格，右圆括号之前也不能有空格。

实例

下面这个例子包含了我们所说的一下规则：

 $b) {
            $foo->bar($arg1);
        } else {
            BazClass::bar($arg2, $arg3);
        }
    }

    final public static function bar()
    {
        // method body
    }
}

二、总结

基础编码规范

代码一定遵循PSR-1的所有规则。

文件

所有php文件一定使用Unix LF换行符作为行结尾。

所有php文件必须使用一个空行结束。

在仅包含php代码的文件中，关闭标签?>一定要省略。

行

行长度一定不能有硬限制。

行长度软限制一定时120个字符；关于软限制，自动代码检查工具一定是warn，而一定不能是error。

行长度应该不超过80个字符；超过80个字符应该被分隔为多个不超过80个字符的子行。

非空行一定不能有结尾空格。

空行可以被用来提高可读性和分隔关联代码段。

每行一定不能超过一个语句。

缩进

代码一定使用四个空格锁紧，一定不能使用tab缩进。

注意: Using only spaces, and not mixing spaces with tabs, helps to avoid problems with diffs, patches, history, and annotations. The use of spaces also makes it easy to insert fine-grained sub-indentation for inter-line alignment.

关键词和系统常量

PHP keywords 一定使用小写。

PHP常量true，false和null一定使用小写。

三、命名空间和use声明

目前，在namespace声明之后一定有一个空行。

所有的use声明一定在namespace声明之后。

每个声明一定只有一个use。

所有的use声明完成后一定有一个空行。

例如：

四、类，属性和方法

术语class指所有的class,interface和trait。

继承和实现

extends和implements关键词一定与类名在同一行。

类的左花括号一定在类名的下一行；右花括号一定在内容的下一行。

implements列表可以被分隔为多个带有一个缩进的行。如果你这样放，列表的第一个元素一定在类名的下一行，每行一定只能有一个接口。

属性

所有属性的可见性必须声明。

var关键词一定不能被定义为一个属性。

每一个语句一定不能定义超过一个属性。

属性名称不应该使用一个下划线去区分protected或者private可见性。

一个属性声明看起来应该像下面这样。

方法

所有方法一定要声明可见性。

Method names SHOULD NOT be prefixed with a single underscore to indicate
protected or private visibility.

Method names MUST NOT be declared with a space after the method name. The
opening brace MUST go on its own line, and the closing brace MUST go on the
next line following the body. There MUST NOT be a space after the opening
parenthesis, and there MUST NOT be a space before the closing parenthesis.

A method declaration looks like the following. Note the placement of
parentheses, commas, spaces, and braces:

4.4. Method Arguments

In the argument list, there MUST NOT be a space before each comma, and there
MUST be one space after each comma.

Method arguments with default values MUST go at the end of the argument
list.

Argument lists MAY be split across multiple lines, where each subsequent line
is indented once. When doing so, the first item in the list MUST be on the
next line, and there MUST be only one argument per line.

When the argument list is split across multiple lines, the closing parenthesis
and opening brace MUST be placed together on their own line with one space
between them.

4.5. abstract, final, and static

When present, the abstract and final declarations MUST precede the
visibility declaration.

When present, the static declaration MUST come after the visibility
declaration.

4.6. Method and Function Calls

When making a method or function call, there MUST NOT be a space between the
method or function name and the opening parenthesis, there MUST NOT be a space
after the opening parenthesis, and there MUST NOT be a space before the
closing parenthesis. In the argument list, there MUST NOT be a space before
each comma, and there MUST be one space after each comma.

bar($arg1);
Foo::bar($arg2, $arg3);

Argument lists MAY be split across multiple lines, where each subsequent line
is indented once. When doing so, the first item in the list MUST be on the
next line, and there MUST be only one argument per line.

bar(
    $longArgument,
    $longerArgument,
    $muchLongerArgument
);

5. Control Structures

The general style rules for control structures are as follows:

• There MUST be one space after the control structure keyword
• There MUST NOT be a space after the opening parenthesis
• There MUST NOT be a space before the closing parenthesis
• There MUST be one space between the closing parenthesis and the opening
  brace
• The structure body MUST be indented once
• The closing brace MUST be on the next line after the body

The body of each structure MUST be enclosed by braces. This standardizes how
the structures look, and reduces the likelihood of introducing errors as new
lines get added to the body.

5.1. if, elseif, else

An if structure looks like the following. Note the placement of parentheses,
spaces, and braces; and that else and elseif are on the same line as the
closing brace from the earlier body.

The keyword elseif SHOULD be used instead of else if so that all control
keywords look like single words.

5.2. switch, case

A switch structure looks like the following. Note the placement of
parentheses, spaces, and braces. The case statement MUST be indented once
from switch, and the break keyword (or other terminating keyword) MUST be
indented at the same level as the case body. There MUST be a comment such as
// no break when fall-through is intentional in a non-empty case body.

5.3. while, do while

A while statement looks like the following. Note the placement of
parentheses, spaces, and braces.

Similarly, a do while statement looks like the following. Note the placement
of parentheses, spaces, and braces.

5.4. for

A for statement looks like the following. Note the placement of parentheses,
spaces, and braces.

5.5. foreach

A foreach statement looks like the following. Note the placement of
parentheses, spaces, and braces.

 $value) {
    // foreach body
}

5.6. try, catch

A try catch block looks like the following. Note the placement of
parentheses, spaces, and braces.

6. Closures

Closures MUST be declared with a space after the function keyword, and a
space before and after the use keyword.

The opening brace MUST go on the same line, and the closing brace MUST go on
the next line following the body.

There MUST NOT be a space after the opening parenthesis of the argument list
or variable list, and there MUST NOT be a space before the closing parenthesis
of the argument list or variable list.

In the argument list and variable list, there MUST NOT be a space before each
comma, and there MUST be one space after each comma.

Closure arguments with default values MUST go at the end of the argument
list.

A closure declaration looks like the following. Note the placement of
parentheses, commas, spaces, and braces:

Argument lists and variable lists MAY be split across multiple lines, where
each subsequent line is indented once. When doing so, the first item in the
list MUST be on the next line, and there MUST be only one argument or variable
per line.

When the ending list (whether of arguments or variables) is split across
multiple lines, the closing parenthesis and opening brace MUST be placed
together on their own line with one space between them.

The following are examples of closures with and without argument lists and
variable lists split across multiple lines.

Note that the formatting rules also apply when the closure is used directly
in a function or method call as an argument.

bar(
    $arg1,
    function ($arg2) use ($var1) {
        // body
    },
    $arg3
);

7. Conclusion

There are many elements of style and practice intentionally omitted by this
guide. These include but are not limited to:

• Declaration of global variables and global constants

• Declaration of functions

• Operators and assignment

• Inter-line alignment

• Comments and documentation blocks

• Class name prefixes and suffixes

• Best practices

Future recommendations MAY revise and extend this guide to address those or
other elements of style and practice.

Appendix A. Survey

In writing this style guide, the group took a survey of member projects to
determine common practices. The survey is retained herein for posterity.

A.1. Survey Data

url,http://www.horde.org/apps/horde/docs/CODING_STANDARDS,http://pear.php.net/manual/en/standards.php,http://solarphp.com/manual/appendix-standards.style,http://framework.zend.com/manual/en/coding-standard.html,https://symfony.com/doc/2.0/contributing/code/standards.html,http://www.ppi.io/docs/coding-standards.html,https://github.com/ezsystems/ezp-next/wiki/codingstandards,http://book.cakephp.org/2.0/en/contributing/cakephp-coding-conventions.html,https://github.com/UnionOfRAD/lithium/wiki/Spec%3A-Coding,http://drupal.org/coding-standards,http://code.google.com/p/sabredav/,http://area51.phpbb.com/docs/31x/coding-guidelines.html,https://docs.google.com/a/zikula.org/document/edit?authkey=CPCU0Us&hgd=1&id=1fcqb93Sn-hR9c0mkN6m_tyWnmEvoswKBtSc0tKkZmJA,http://www.chisimba.com,n/a,https://github.com/Respect/project-info/blob/master/coding-standards-sample.php,n/a,Object Calisthenics for PHP,http://doc.nette.org/en/coding-standard,http://flow3.typo3.org,https://github.com/propelorm/Propel2/wiki/Coding-Standards,http://developer.joomla.org/coding-standards.html
voting,yes,yes,yes,yes,yes,yes,yes,yes,yes,yes,yes,yes,yes,yes,yes,no,no,no,?,yes,no,yes
indent_type,4,4,4,4,4,tab,4,tab,tab,2,4,tab,4,4,4,4,4,4,tab,tab,4,tab
line_length_limit_soft,75,75,75,75,no,85,120,120,80,80,80,no,100,80,80,?,?,120,80,120,no,150
line_length_limit_hard,85,85,85,85,no,no,no,no,100,?,no,no,no,100,100,?,120,120,no,no,no,no
class_names,studly,studly,studly,studly,studly,studly,studly,studly,studly,studly,studly,lower_under,studly,lower,studly,studly,studly,studly,?,studly,studly,studly
class_brace_line,next,next,next,next,next,same,next,same,same,same,same,next,next,next,next,next,next,next,next,same,next,next
constant_names,upper,upper,upper,upper,upper,upper,upper,upper,upper,upper,upper,upper,upper,upper,upper,upper,upper,upper,upper,upper,upper,upper
true_false_null,lower,lower,lower,lower,lower,lower,lower,lower,lower,upper,lower,lower,lower,upper,lower,lower,lower,lower,lower,upper,lower,lower
method_names,camel,camel,camel,camel,camel,camel,camel,camel,camel,camel,camel,lower_under,camel,camel,camel,camel,camel,camel,camel,camel,camel,camel
method_brace_line,next,next,next,next,next,same,next,same,same,same,same,next,next,same,next,next,next,next,next,same,next,next
control_brace_line,same,same,same,same,same,same,next,same,same,same,same,next,same,same,next,same,same,same,same,same,same,next
control_space_after,yes,yes,yes,yes,yes,no,yes,yes,yes,yes,no,yes,yes,yes,yes,yes,yes,yes,yes,yes,yes,yes
always_use_control_braces,yes,yes,yes,yes,yes,yes,no,yes,yes,yes,no,yes,yes,yes,yes,no,yes,yes,yes,yes,yes,yes
else_elseif_line,same,same,same,same,same,same,next,same,same,next,same,next,same,next,next,same,same,same,same,same,same,next
case_break_indent_from_switch,0/1,0/1,0/1,1/2,1/2,1/2,1/2,1/1,1/1,1/2,1/2,1/1,1/2,1/2,1/2,1/2,1/2,1/2,0/1,1/1,1/2,1/2
function_space_after,no,no,no,no,no,no,no,no,no,no,no,no,no,no,no,no,no,no,no,no,no,no
closing_php_tag_required,no,no,no,no,no,no,no,no,yes,no,no,no,no,yes,no,no,no,no,no,yes,no,no
line_endings,LF,LF,LF,LF,LF,LF,LF,LF,?,LF,?,LF,LF,LF,LF,?,,LF,?,LF,LF,LF
static_or_visibility_first,static,?,static,either,either,either,visibility,visibility,visibility,either,static,either,?,visibility,?,?,either,either,visibility,visibility,static,?
control_space_parens,no,no,no,no,no,no,yes,no,no,no,no,no,no,yes,?,no,no,no,no,no,no,no
blank_line_after_php,no,no,no,no,yes,no,no,no,no,yes,yes,no,no,yes,?,yes,yes,no,yes,no,yes,no
class_method_control_brace,next/next/same,next/next/same,next/next/same,next/next/same,next/next/same,same/same/same,next/next/next,same/same/same,same/same/same,same/same/same,same/same/same,next/next/next,next/next/same,next/same/same,next/next/next,next/next/same,next/next/same,next/next/same,next/next/same,same/same/same,next/next/same,next/next/next

A.2. Survey Legend

indent_type:
The type of indenting. tab = “Use a tab”, 2 or 4 = “number of spaces”

line_length_limit_soft:
The “soft” line length limit, in characters. ? = not discernible or no response, no means no limit.

line_length_limit_hard:
The “hard” line length limit, in characters. ? = not discernible or no response, no means no limit.

class_names:
How classes are named. lower = lowercase only, lower_under = lowercase with underscore separators, studly = StudlyCase.

class_brace_line:
Does the opening brace for a class go on the same line as the class keyword, or on the next line after it?

constant_names:
How are class constants named? upper = Uppercase with underscore separators.

true_false_null:
Are the true, false, and null keywords spelled as all lower case, or all upper case?

method_names:
How are methods named? camel = camelCase, lower_under = lowercase with underscore separators.

method_brace_line:
Does the opening brace for a method go on the same line as the method name, or on the next line?

control_brace_line:
Does the opening brace for a control structure go on the same line, or on the next line?

control_space_after:
Is there a space after the control structure keyword?

always_use_control_braces:
Do control structures always use braces?

else_elseif_line:
When using else or elseif, does it go on the same line as the previous closing brace, or does it go on the next line?

case_break_indent_from_switch:
How many times are case and break indented from an opening switch statement?

function_space_after:
Do function calls have a space after the function name and before the opening parenthesis?

closing_php_tag_required:
In files containing only PHP, is the closing ?> tag required?

line_endings:
What type of line ending is used?

static_or_visibility_first:
When declaring a method, does static come first, or does the visibility come first?

control_space_parens:
In a control structure expression, is there a space after the opening parenthesis and a space before the closing parenthesis? yes = if ( $expr ), no = if ($expr).

blank_line_after_php:
Is there a blank line after the opening PHP tag?

class_method_control_brace:
A summary of what line the opening braces go on for classes, methods, and control structures.

A.3. Survey Results

indent_type:
    tab: 7
    2: 1
    4: 14
line_length_limit_soft:
    ?: 2
    no: 3
    75: 4
    80: 6
    85: 1
    100: 1
    120: 4
    150: 1
line_length_limit_hard:
    ?: 2
    no: 11
    85: 4
    100: 3
    120: 2
class_names:
    ?: 1
    lower: 1
    lower_under: 1
    studly: 19
class_brace_line:
    next: 16
    same: 6
constant_names:
    upper: 22
true_false_null:
    lower: 19
    upper: 3
method_names:
    camel: 21
    lower_under: 1
method_brace_line:
    next: 15
    same: 7
control_brace_line:
    next: 4
    same: 18
control_space_after:
    no: 2
    yes: 20
always_use_control_braces:
    no: 3
    yes: 19
else_elseif_line:
    next: 6
    same: 16
case_break_indent_from_switch:
    0/1: 4
    1/1: 4
    1/2: 14
function_space_after:
    no: 22
closing_php_tag_required:
    no: 19
    yes: 3
line_endings:
    ?: 5
    LF: 17
static_or_visibility_first:
    ?: 5
    either: 7
    static: 4
    visibility: 6
control_space_parens:
    ?: 1
    no: 19
    yes: 2
blank_line_after_php:
    ?: 1
    no: 13
    yes: 8
class_method_control_brace:
    next/next/next: 4
    next/next/same: 11
    next/same/same: 1
    same/same/same: 6

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