[PHP] PSR brief specification

PSR is a series of specifications about PHP development. There are several versions. I learned it superficially, but I still hope to check the specifications from time to time. In order to facilitate memory and follow, I picked out the necessary keywords and made a Simply necessary normative records. (Just a brick mover...)
https://github.com/PizzaLiu/PHP-FIG
http://segmentfault.com/a/1190000002521577

PSR-0(deprecated)

PSR-1 Basic Code Specification

PSR-2 Code Style Specification

PSR-2 Supplementary Documentation

PSR-3 log interface specification

PSR-4 automatically loaded

PSR-5 and PSR-6 voting has not passed yet

php code file must start with

PHP code files must be encoded in UTF-8 without BOM;

Namespaces and classes must comply with PSR’s autoloading specification: one of PSR-0 or PSR-4;

The naming of classes must follow the StudlyCaps camel case naming convention starting with an uppercase letter;

All letters of constants in the class must be capitalized, and words are separated by underscores;

Method names must comply with camelCase-style camelCase naming convention starting with lowercase.

PHP code must use long tag or = ?> short output tag; other custom tags must not be used.

Namespace and class naming must comply with PSR-0.

Code for PHP 5.3 and later versions must use formal namespaces.

Each class is an independent file, and the namespace has at least one level: the top-level organization name (vendor name)

Code must follow the coding specifications in PSR-1.

Code must be indented using 4 spaces instead of the tab key.

Note: The advantage of using spaces instead of tab keys for indentation is to avoid confusion when comparing code differences, patching, reviewing code, and comments. Also, use spaces for indentation to make alignment easier.

A blank line must be inserted after each namespace declaration statement and use declaration block.

The opening curly brace ({) of the class must be written on its own line after the function declaration, and the closing curly brace (}) must also be written on its own line after the function body.

The opening curly brace ({) of the method must be written on its own line after the function declaration, and the closing curly brace (}) must also be written on its own line after the function body.

The properties and methods of the class must add access modifiers (private, protected and public), abstract and final must be declared before the access modifier, and static must be declared after the access modifier.

There must be a space after the keyword of the control structure, but it must not be when calling a method or function.

The opening brace ({) of the control structure must be written on the same line as the declaration, and the closing brace (}) must be written on its own line after the body.

There must be no spaces after the opening left bracket and before the closing right bracket of the control structure.

All PHP files must use Unix LF (linefeed) as the line terminator.

All PHP files must end with a blank line.

Pure PHP code files must omit the final ?> closing tag.

There must not be more than one statement per line.

There must be no extra spaces after non-blank lines.

All PHP keywords must be in lowercase.

The constants true, false and null must also be all lowercase.

A complete class name must have the following structure:

When loading the corresponding file based on the complete class name

PHP code should only define declarations such as classes, functions, constants, etc., or other operations that will produce subordinate effects (such as generating file output and modifying .ini configuration files, etc.). You can only choose one of the two;

The attribute naming of the class can follow the camel case starting with upper case ($StudlyCaps), the camel case starting with lower case ($camelCase), or the underline delimited format ($under_score). This specification does not make it mandatory, but no matter which naming is followed methods should be consistent within a certain range.

The number of characters per line should be softly kept within 80. In theory, it must not exceed 120, but there must be no hard limit.

Blank lines make it easier to read code and help break up code into chunks.