A function-based API can be (almost) automatically generated from methods -- all you need is a customized import sub. A default object is created during import and each package using the module has a private default object. This approach usually works a bit better than Flexx's because (1) it avoids creating lots of temporary objects, and (2) there's a long-lived object around to hold module state, so all the state-setting methods still work.
I wouldn't recommend the CGI.pm module for studying this technique. CGI.pm is difficult to understand because of its long and glorious history. Take a look at my code below, read the docs on packages and symbolic references, look at Exporter.pm and then you're ready to crack open CGI.pm.
## MyClass.pm
package MyClass;
use strict;
my @export = qw(verbose isFile);
sub new {
my ($class, %args) = @_;
my $self = {verbose => $args{verbose} || 0};
return bless $self, $class;
}
sub verbose {
my $self = shift;
$self->{verbose} = shift if @_;
return $self->{verbose};
}
sub isFile {
my ($self, $file) = @_;
my $found = -f $file;
if ($self->verbose) {
print STDERR "$file ", ($found ? 'found' : 'not found'), "\n";
}
return $found;
}
sub import {
my $module = shift;
my $mode = shift || ':methods';
if ($mode eq ':functions') {
no strict 'refs';
my ($package) = caller();
my $object = MyClass->new(@_);
foreach my $name (@export) {
my $sub = $MyClass::{$name};
*{$package.'::'.$name} = sub {
&{$sub}($object, @_)
};
}
}
}
1;
## test.pl
package verbose_main;
use strict;
use MyClass (':functions', verbose => 1);
sub test {
if (isFile('MyClass.pm')) {
print "ok\n";
}
if (verbose()) {
print "verbose mode on\n";
}
}
package quiet_main;
use strict;
use MyClass (':functions');
sub test {
if (isFile('MyClass.pm')) {
print "ok\n";
}
verbose(1);
if (isFile('NotFound')) {
print "ok\n";
}
}
package oo_main;
use strict;
use MyClass;
my $env = MyClass->new(verbose => 1);
sub test {
if ($env->isFile('MyClass.pm')) {
print "ok\n";
}
}
package main;
use strict;
verbose_main::test();
quiet_main::test();
oo_main::test();
