[%# # IMPORTANT NOTE # This documentation is generated automatically from source # templates. Any changes you make here may be lost. # # The 'docsrc' documentation source bundle is available for download # from http://www.template-toolkit.org/docs.html and contains all # the source templates, XML files, scripts, etc., from which the # documentation for the Template Toolkit is built. -%] [% META book = 'Modules' page = 'Base' %] [% WRAPPER toc; PROCESS tocitem title ="SYNOPSIS" subs = []; PROCESS tocitem title ="DESCRIPTION" subs = []; PROCESS tocitem title ="PUBLIC METHODS" subs = [ "new(\\%config)", "error(\$msg, ...)", "debug(\$msg, ...)" ]; PROCESS tocitem title ="AUTHOR" subs = []; PROCESS tocitem title ="VERSION" subs = []; PROCESS tocitem title ="COPYRIGHT" subs = []; PROCESS tocitem title ="SEE ALSO" subs = []; END %] [% WRAPPER section title="SYNOPSIS" -%]
    package My::Module;
    use base qw( Template::Base );
    sub _init {
	my ($self, $config) = @_;
	$self->{ doodah } = $config->{ doodah }
	    || return $self->error("No 'doodah' specified");
	return $self;
    }
    package main;
    my $object = My::Module->new({ doodah => 'foobar' })
        || die My::Module->error();
[%- END %] [% WRAPPER section title="DESCRIPTION" -%]

Base class module which implements a constructor and error reporting functionality for various Template Toolkit modules.

[%- END %] [% WRAPPER section title="PUBLIC METHODS" -%][% WRAPPER subsection title = "new(\\%config)" -%]

Constructor method which accepts a reference to a hash array or a list of 'name => value' parameters which are folded into a hash. The _init() method is then called, passing the configuration hash and should return true/false to indicate success or failure. A new object reference is returned, or undef on error. Any error message raised can be examined via the error() class method or directly via the package variable ERROR in the derived class.

    my $module = My::Module->new({ ... })
        || die My::Module->error(), "\n";
    my $module = My::Module->new({ ... })
        || die "constructor error: $My::Module::ERROR\n";
[%- END %] [% WRAPPER subsection title = "error(\$msg, ...)" -%]

May be called as an object method to get/set the internal _ERROR member or as a class method to get/set the $ERROR variable in the derived class's package.

    my $module = My::Module->new({ ... })
        || die My::Module->error(), "\n";
    $module->do_something() 
	|| die $module->error(), "\n";

When called with parameters (multiple params are concatenated), this method will set the relevant variable and return undef. This is most often used within object methods to report errors to the caller.

    package My::Module;
    sub foobar {
	my $self = shift;
	# some other code...
	return $self->error('some kind of error...')
	    if $some_condition;
    }
[%- END %] [% WRAPPER subsection title = "debug(\$msg, ...)" -%]

Generates a debugging message by concatenating all arguments passed into a string and printing it to STDERR. A prefix is added to indicate the module of the caller.

    package My::Module;
    sub foobar {
	my $self = shift;
	$self->debug('called foobar()');
	# some other code...
    }

When the foobar() method is called, the following message is sent to STDERR:

    [My::Module] called foobar()

Objects can set an internal DEBUG value which the debug() method will examine. If this value sets the relevant bits to indicate DEBUG_CALLER then the file and line number of the caller will be appened to the message.

    use Template::Constants qw( :debug );
    my $module = My::Module->new({
        DEBUG => DEBUG_SERVICE | DEBUG_CONTEXT | DEBUG_CALLER,
    });
    $module->foobar();

This generates an error message such as:

    [My::Module] called foobar() at My/Module.pm line 6
[%- END %] [%- END %] [% WRAPPER section title="AUTHOR" -%]

Andy Wardley <abw@wardley.org>

[% ttlink('http://wardley.org/', 'http://wardley.org/') -%]

[%- END %] [% WRAPPER section title="VERSION" -%]

2.77, distributed as part of the Template Toolkit version 2.19, released on 27 April 2007.

[%- END %] [% WRAPPER section title="COPYRIGHT" -%]
  Copyright (C) 1996-2007 Andy Wardley.  All Rights Reserved.

This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

[%- END %] [% WRAPPER section title="SEE ALSO" -%]

[% ttlink('Template', 'Template') -%]

[%- END %]