[Templates-cvs] cvs commit: TT3/examples README directive.pl

[cvs@template-toolkit.org]

cvs         04/12/11 13:57:37

  Added:       examples README directive.pl
  Log:
  * added new examples and test templates
  
  Revision  Changes    Path
  1.1                  TT3/examples/README
  
  Index: README
  ===================================================================
  This directory contains some examples of TT3 in action.
  
    tt3.pl        # process a template via the Template module
    compiler.pl   # shows the Perl code generated by the compiler
    directive.pl  # writing a custom directive
    htmlt.pl      # proof-of-concept for HTML::Template-like language
    scanner.pl    # creating a custom template scanner
  
  
  1.1                  TT3/examples/directive.pl
  
  Index: directive.pl
  ===================================================================
  #!/usr/bin/perl -w                                            # -*- perl -*-
  #
  # This example shows how a custom directive can be created.  We
  # define a My::Directive::Hello directive to parse an imaginary
  # HELLO directive, and also a custom generator to generate Perl
  # code for it.  Then we plug it all in and compile a template.
  #
  
  use strict;
  use warnings;
  use lib qw( ../lib ./lib );
  use Template::TT3::Compiler;
  use Template::Directive;
  use Template::Generator::Perl;
  
  # run with '-d' option to enable debugging
  my $DEBUG = 
  $Template::Tagset::DEBUG =
  $Template::Tag::Directive::DEBUG =
  $Template::Factory::Modules::DEBUG =
  $Template::Factory::DEBUG =
  grep(/^--?d(ebug)?/, @ARGV);
  
  #------------------------------------------------------------------------
  # First we define an object to parse the directive into a structured
  # expression.  The Template::Parser (in $match->{ parser }) does most
  # of the hard work.
  #------------------------------------------------------------------------
  
  package My::Directive::Hello;
  use base 'Template::Directive';
  
  our $KEYWORD = 'HELLO';
  
  sub parse {
      my ($self, $textref, $handler, $match) = @_;
  
      print STDERR "parsing HELLO directive at line $match->{ line }\n";
  
      # just like the INCLUDE directive, our HELLO directive 
      # expects a list of one or more paths (separated by '+'),
      # and then an optional list of parameters
  
      my $parser = $match->{ parser };
      my $paths  = $parser->parse_paths($textref)
          || return $self->error('missing paths in ',
                                 $self->keyword($match),
                                 ' directive');
      my $params = $parser->parse_params($textref);
  
      return $handler->expr( hello => $paths, $params );
  }
  
  
  #------------------------------------------------------------------------
  # next we subclass the Perl generator to generate some Perl code for
  # the directive.  We also redefine the template_modules() method to 
  # add our Template::Resource::Hello object to the list of modules loaded
  # by this template.  This module (not shown) defines the hello() method 
  # in the Template::Context that our generated code is going to call, and
  # implements whatever particular functionally is required of HELLO.
  #------------------------------------------------------------------------
  
  package My::Generator::Perl;
  use base 'Template::Generator::Perl';
  
  sub generate_hello {
      my ($self, $paths, $params) = @_;
      $paths  = $self->generate_paths($paths);
      $params = $self->generate_params($params);
      return $self->output("\$context->hello($paths, $params)");
  }
  
  sub template_modules {
      my $self = shift;
      my $modules = $self->SUPER::template_modules();
      return <<EOF;
  $modules
  use My::Resource::Hello;
  EOF
  }
  
  
  #------------------------------------------------------------------------
  # now we go ahead and use it.
  #------------------------------------------------------------------------
  
  my $compiler = Template::TT3::Compiler->new({
      directives => {
          HELLO => 'My::Directive::Hello', 
          hello => 'My::Directive::Hello',
      },
      loaded => 'HELLO hello',
      generator => My::Generator::Perl->new( pretty => 1 ),
  }) || die Template::TT3::Compiler->error();
  
  # read input from __DATA__ section
  local $/ = undef;
  my $input = <DATA>;
  
  # compile input template into Perl code
  my $output = $compiler->compile($input, name => 'compiler example')
      || die $compiler->error();
  
  # Look ma!  A compiled template!
  print "-- input --\n",
        $input, "\n",
        "-- output --\n",
        $output, "\n";
  
  
  __DATA__
  
  [% HELLO world %]
  
  [% HELLO world + 'his wife'
        title = 'Global Greeting'
  %]
  
  Also works in side-effect:
  
  [% HELLO world IF happy %]