patch

Here's a sample usage:

  sub foo {
    my $count = shift;
    return 'foo' x $count;
  }
  
  Class::MakeMethods::Composite::Universal->make(
    -ForceInstall => 1,
    patch => {
      name => 'foo',
      pre_rules => [
        sub { 
          my $method = pop @_;
          if ( ! scalar @_ ) {
            @{ $method->{args} } = ( 2 );
          }
        },
        sub { 
          my $method = pop @_;
          my $count = shift;
          if ( $count > 99 ) {
            Carp::confess "Won't foo '$count' -- that's too many!"
          }
        },
      ],
      post_rules => [
        sub { 
          my $method = pop @_;
          if ( ref $method->{result} eq 'SCALAR' ) {
            ${ $method->{result} } =~ s/oof/oozle-f/g;
          } elsif ( ref $method->{result} eq 'ARRAY' ) {
            map { s/oof/oozle-f/g } @{ $method->{result} };
          }
        } 
      ],
    },
  );

make_patch

Provides the '-ForceInstall' flag, which is required to ensure that the patched subroutine replaces the original.

For example, one could add logging to an existing method as follows:

  Class::MakeMethods::Composite::Universal->make_patch(
    -TargetClass => 'SomeClass::OverYonder',
    name => 'foo',
    pre_rules => [ 
      sub { 
        my $method = pop; 
        warn "Arguments for foo:", @_ 
      } 
    ]
    post_rules => [ 
      sub { 
        warn "Result of foo:", Class::MakeMethods::Composite->CurrentResults 
      } 
    ]
  );