PHP | ReflectionExtension __toString() Function

The ReflectionExtension::__toString() function is an inbuilt function in PHP which is used to return the string representation of the specified extension object.

Syntax:

ReflectionExtension::__toString()

Parameters: This function does not accept any parameter.

Return Value: This function returns the string representation of the specified extension object.

Below programs illustrate the ReflectionExtension::__toString() function in PHP:
Program_1:

<?php

// Defining an extension
$A = 'DOM';

// Using ReflectionExtension() over the
// specified extension
$extension = new ReflectionExtension($A);

// Calling the __toString() function
$B = $extension->__toString();

// Getting the string representation of
// the specified extension object.
var_dump($B);
?>

Output:

string(98219) "Extension [ <persistent> extension #18 dom version 20031129 ] {

  - Dependencies {
    Dependency [ libxml (Required) ]
    Dependency [ domxml (Conflicts) ]
  }

  - Constants [45] {
    Constant [ integer XML_ELEMENT_NODE ] { 1 }
    . . .
    Constant [ integer DOM_VALIDATION_ERR ] { 16 }
  }


        Method [ <internal:dom, inherits DOMNode> public method setUserData ] {

          - Parameters [3] {
            Parameter #0 [ <required> $key ]
            Parameter #1 [ <required> $data ]
            Parameter #2 [ <required> $handler ]
          }
        }
        . . .

        Method [ <internal:dom> public method registerPhpFunctions ] {

          - Parameters [0] {
          }
        }
      }
    }
  }
}
"

Program_2:

<?php

// Using ReflectionExtension() over
// an extension xml
$extension = new ReflectionExtension('xml');

// Calling the __toString() function and
// Getting the string representation of
// the specified extension object.
var_dump($extension->__toString());
?>

Output:

string(6209) "Extension [ <persistent> extension #15 xml version 7.0.33-0ubuntu0.16.04.7 ] {

  - Dependencies {
    Dependency [ libxml (Required) ]
  }

  - Constants [27] {
    Constant [ integer XML_ERROR_NONE ] { 0 }
    . . .
    Constant [ string XML_SAX_IMPL ] { libxml }
  }

  - Functions {
    Function [ <internal:xml> function xml_parser_create ] {

      - Parameters [1] {
        Parameter #0 [ <optional> $encoding ]
      }
    }
    . . . 
    Function [ <internal:xml> function utf8_decode ] {

      - Parameters [1] {
        Parameter #0 [ <required> $data ]
      }
    }
  }
}
"

Reference: https://www.php.net/manual/en/reflectionextension.tostring.php