Re: reflection in perl

[Todd W]

"Michael Seele" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
> hi,
> i'm new to perl and i want to know if perl has reflection like java?
> how can i acces reflection and how powerfull is the reflection in perl?
> thx mseele
>
Perls reflection support is probably my most favorite thing about perl.
Basically, reflection is built in to perl. No reflection API is needed. You
just use scalar variables that contain class and method names in place of
the actual names and everything works dynamically:

use warnings;
use strict;

package Base;

sub new {
  my $class = shift();
  my $self = bless( { }, $class );
  return( $self );
}

our $line = 1;
sub print {
  my $class = shift();
  print( $line, ': ', @_, "\n" );
  $line++;
}

sub foo {
  my $proto = shift();
  $proto->print('Hello from ', (ref($proto) or $proto), '->foo');
}

sub bar {
  my $proto = shift();
  $proto->print('Hello from ', (ref($proto) or $proto), '->bar');
}

package ClassA;
use base qw/Base/;

sub foo {
  my $proto = shift();
  #do work specific for this class, then...
  $proto->SUPER::foo();
}

sub bar {
  my $proto = shift();
  #do work specific for this class, then...
  $proto->SUPER::bar();
}

package ClassB;
use base qw/Base/;

sub foo {
  my $proto = shift();
  #do work specific for this class, then...
  $proto->SUPER::foo();
}

sub bar {
  my $proto = shift();
  #do work specific for this class, then...
  $proto->SUPER::bar();
}

package main;

foreach my $class ( qw/ClassA ClassB/ ) {
  my $obj = $class->new();
  foreach my $method ( qw/foo bar baz/ ) {
    if ( $obj->can( $method ) ) {
      $obj->$method();
    } else {
      $class->print("$obj cant $method");
    }
  }
}

output:

1: Hello from ClassA->foo
2: Hello from ClassA->bar
3: ClassA=HASH(0x15d5218) cant baz
4: Hello from ClassB->foo
5: Hello from ClassB->bar
6: ClassB=HASH(0x1a8941c) cant baz

Todd W.





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