The ReflectionParameter class

(PHP 5, PHP 7)

Introduction

The ReflectionParameter class retrieves information about function's or method's parameters.

To introspect function parameters, first create an instance of the ReflectionFunction or ReflectionMethod classes and then use their ReflectionFunctionAbstract::getParameters() method to retrieve an array of parameters.

Class synopsis

ReflectionParameter implements Reflector {

/* Properties */

public $name ;

/* Methods */

public bool allowsNull ( void )

public bool canBePassedByValue ( void )

final private void __clone ( void )

public __construct ( string $function , string $parameter )

public static string export ( string $function , string $parameter [, bool $return ] )

public ReflectionClass getClass ( void )

public ReflectionClass getDeclaringClass ( void )

public ReflectionFunctionAbstract getDeclaringFunction ( void )

public mixed getDefaultValue ( void )

public string getDefaultValueConstantName ( void )

public string getName ( void )

public int getPosition ( void )

public ReflectionType getType ( void )

public bool hasType ( void )

public bool isArray ( void )

public bool isCallable ( void )

public bool isDefaultValueAvailable ( void )

public bool isDefaultValueConstant ( void )

public bool isOptional ( void )

public bool isPassedByReference ( void )

public bool isVariadic ( void )

public string __toString ( void )

}

Properties

name: Name of the parameter. Read-only, throws ReflectionException in attempt to write.

ReflectionParameter::allowsNull — Checks if null is allowed
ReflectionParameter::canBePassedByValue — Returns whether this parameter can be passed by value
ReflectionParameter::__clone — Clone
ReflectionParameter::__construct — Construct
ReflectionParameter::export — Exports
ReflectionParameter::getClass — Get the type hinted class
ReflectionParameter::getDeclaringClass — Gets declaring class
ReflectionParameter::getDeclaringFunction — Gets declaring function
ReflectionParameter::getDefaultValue — Gets default parameter value
ReflectionParameter::getDefaultValueConstantName — Returns the default value's constant name if default value is constant or null
ReflectionParameter::getName — Gets parameter name
ReflectionParameter::getPosition — Gets parameter position
ReflectionParameter::getType — Gets a parameter's type
ReflectionParameter::hasType — Checks if parameter has a type
ReflectionParameter::isArray — Checks if parameter expects an array
ReflectionParameter::isCallable — Returns whether parameter MUST be callable
ReflectionParameter::isDefaultValueAvailable — Checks if a default value is available
ReflectionParameter::isDefaultValueConstant — Returns whether the default value of this parameter is constant
ReflectionParameter::isOptional — Checks if optional
ReflectionParameter::isPassedByReference — Checks if passed by reference
ReflectionParameter::isVariadic — Checks if the parameter is variadic
ReflectionParameter::__toString — To string

User Contributed Notes

fgm at riff dot org

7 years ago


The note about the signature of the ReflectionParameter constructor is actually incomplete, at least in 5.2.5: it is possible to use an integer for the second parameter, and the constructor will use it to return the n-th parameter.



This allows you to obtain proper ReflectionParameter objects even when documenting code from extensions which (strangely enough) define several parameters with the same name. The string-based constructor always returns the first parameter with the matching name, whereas the integer-based constructor correctly returns the n-th parameter.



So, in short, this works:

<?php

// supposing the extension defined something like:

// Some_Class::someMethod($a, $x, $y, $x, $y)

$p = new ReflectionParameter(array('Some_Class', 'someMethod'), 4);

// returns the last parameter, whereas

$p = new ReflectionParameter(array('Some_Class', 'someMethod'), 'y');

// always returns the first $y at position 2

?>

killgecNOFSPAM at gmail dot com

8 years ago


Signature of constructor of ReflectionParameter correctly is:



public function __construct(array/string $function, string $name);



where $function is either a name of a global function, or a class/method name pair.

massimo at mmware dot it