Quizzer::AutoSelect - automatic FrontEnd selection library.

Quizzer documentation

Contained in the Quizzer distribution.

Index

NAME
DESCRIPTION
METHODS
- frontend
AUTHOR

Code Index:

package Quizzer::AutoSelect
- frontend
EOF

NAME

Quizzer::AutoSelect -- automatic FrontEnd selection library.

DESCRIPTION

This library makes it easy to create FrontEnd and ConfModule objects. It starts with the desired type of object, and tries to make it. If that fails, it progressivly falls back to other types.

METHODS

frontend

Creates and returns a FrontEnd object.

AUTHOR

Joey Hess <joey@kitenet.net>

Quizzer documentation

Contained in the Quizzer distribution.

#!/usr/bin/perl -w

package Quizzer::AutoSelect;
use strict;
use Quizzer::Config;
use Quizzer::Log ':all';

my $VERSION='0.01';

my %fallback=(
	# preferred frontend		# fall back to
	'Web'			=>	'Gtk',
	'Dialog'		=>	'Text',
	'Gtk'			=>	'Dialog',
	'Text'			=>	'Dialog',
);

my $frontend;
my $type;

sub frontend {
	my $script=shift;

	$type=Quizzer::Config::frontend() unless $type;

	my %seen;
	while ($type ne '') {
		debug 1, "trying frontend $type" ;
		$frontend=eval qq{
						use Quizzer::FrontEnd::$type;
						Quizzer::FrontEnd::$type->new();
				};
		last if defined $frontend;
		
		warn "failed to initialize $type frontend";
		debug 1, "(Error: $@)";

		# Only try each type once to prevent loops.
		$seen{$type}=1;
		$type=$fallback{$type};
		last if $seen{$type};

		warn "falling back to $type frontend" if $type ne '';
	}
	
	if (! defined $frontend) {
		# Fallback to noninteractive as a last resort.
		$frontend=eval qq{
						use Quizzer::FrontEnd::Noninteractive;
						Quizzer::FrontEnd::Noninteractive->new();
				};
		die "Unable to start a frontend: $@" unless defined $frontend;
	}

	return $frontend;
}