snippet ariels Remember <tt>::*</tt> and <tt>-&gt;*</tt> from C++? If you do, you probably hate them. <p> A pointer to a member function lets you store a particular method in a variable and then apply it to objects. Here's how to get them in Perl. <p> It's a bit long, but almost all of it isn't code... <CODE> # Perl "pointer to member function" abstraction package PMF; use strict; use Carp; sub new { my ($class,$name) = @_; $name =~ /^[A-Za-z0-9_]\w*$/ or croak "Bad method name \"$name\""; bless eval <<"END_CODE", $class; sub { my \$self = shift; \$self->$name(\@_) } END_CODE } sub call { my $self = shift; $self->(@_) } package PMF::able; sub call { # permute our args my $self = shift; my $pmf = shift; $pmf->($self,@_); } =head1 NAME PMF - pointer to member function in Perl =head1 SYNOPSIS my $p = PMF->new('print'); my $x = ClassWithPrintMethod->new(17); $p->($x, 'foo'); # call $x->print('foo') $p->call($x, 'foo'); # call $x->print('foo') in another way package MyClass; use vars qw/@ISA/; @ISA = qw/PMF::able/; # ... package main; my $y = MyClass->new('xyz'); $y->call($p, 42); # call $y->print(42) =head1 DESCRIPTION C<PMF> gives you pointers to member functions. A PMF is the abstraction of calling a particular method of an object, similar to the C<::*> / C<-E<gt>*> mess of C++. To create a PMF, pass C<new> the name of the method you want to call. C<PMF::new> creates a code object that calls that method of any object (contrast C++ pointers to member functions, which are restricted to subclasses of some root class). Lacking a better dispatch syntax, you apply a PMF C<$pmf> to an object C<$obj> by saying C<$pmf-E<gt>($obj, I<args...>)>. =head1 ALTERNATE CALLING SYNTAX If you would rather say C<$obj-E<gt>call($pmf, I<args...>)>, you need to make the class of C<$obj> inherit from the mixin class C<PMF::able>, which provides exactly this C<call> method. If you wish to avoid changing the class of C<$obj>, you can still use the alternate syntax by creating your objects in an appropriate dummy class: package MyClass2; use vars qw/@ISA/; @ISA = qw/ClassWithPrintMethod PMF::able/; # empty package body! package main; my $z = MyClass2->new(19); $z->call($p, 'foo'); =head1 NOTES / BUGS =over 4 =item * A PMF is not really an object. It I<is> blessed into the class C<PMF>, but has no methods except C<call>! =item * The syntax is horrible. At least it is not as bad as in C++. =item * C<PMF::able> is probably more confusing than useful. =head1 AUTHOR Ariel Scolnicov C<E<lt><gt>> =cut 1; </CODE>