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Config-TT2-0.53
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 / Config::TT2

NAME

Config::TT2 - Reading configuration files with the Template-Toolkit parser.

ABSTRACT

Define configuration files in the powerful, flexible and extensible Template-Toolkit syntax.

SYNOPSIS

    use Config::TT2;

    my $ctt2      = Config::TT2->new;
    my $cfg_stash = $ctt2->process($file);

DESCRIPTION

Config::TT2 extends the Template-Toolkit aka TT2 in a very special way:

It returns the VARIABLES STASH instead of the template text!

The TT2 syntax is very powerful, flexible and extensible. One of the key features of TT2 is the ability to bind template variables to any kind of Perl data: scalars, lists, hash arrays, sub-routines and objects.

See Template::Manual::Variables for a reference.

E.g. this Template-Toolkit config

  [%                        # tt2 directive start-tag
    scalar = 'string'       # strings in single or double quotes

    array = [ 10 20 30 ]    # commas are optional
    rev   = array.reverse   # powerful virtual methods
    item  = array.0         # interpolate previous value

    hash = { foo = 'bar'    # hashes to any depth
             moo = array    # points to above arrayref
           }
  %]                        # tt2 directive end-tag

is returned as a perl datastructure:

   'scalar' => 'string'
   'array' => ARRAY(0x8ad2708)
      0  10
      1  20
      2  30
   'rev' => ARRAY(0x8afe740)
      0  30
      1  20
      2  10
   'item' => 10
   'hash' => HASH(0x8afe160)
      'foo' => 'bar'
      'moo' => ARRAY(0x8ad2708)
         -> REUSED_ADDRESS

METHODS

new(%config)

The new() constructor method instantiates a new Config::TT2 object. This method croaks on error.

Configuration items may be passed as a list of items or a hash array:

    my $ctt2 = Config::TT2->new(
        ABSOLUTE => 0,
        DEBUG    => 'all',
    );

The supported configuration options are the same as for Template, please see the Template::Manual::Config as a reference and the LIMITATIONS section below.

The preset default options which differ from the Template default options are:

  STRICT     = 1   # undefined vars or values cause exceptions
  ABSOLUTE   = 1   # files with absolute filenames allowed
  RELATIVE   = 1   # files with relative filenames allowed
  CACHE_SIZE = 0   # don't cache compiled config files

process($config, $variables)

The process() method is called to process a config file or string. The first parameter indicates the input as one of: a filename; a reference to a text string containing the config text; or a file handle reference, from which the config can be read.

A reference to a hash array may be passed as the second parameter, containing definitions of input variables.

    $stash = $ctt2->process( '.app.cfg', {foo => $ENV{APP_FOO}} );

The returned datastructure is a Template::Stash object. You may access the key and values through normal perl dereferencing:

   $item = $stash->{hash}{moo}[0];

or via the Template::Stash->get method like:

   $item = $stash->get('hash.moo.0');

For debugging purposes you can even request the template output from the process method:

  ($stash, $output) = $ctt2->process( $config );

The method croaks on error.

LIMITATIONS

The Template-Toolkit processor uses the toplevel variables template und component for meta information during template file processing. You MUST NOT define or redefine these toplevel variables at object creation, processing or within the config files.

See the section "Special Variables" in Template::Manual::Variables.

The process method purges these toplevel variables unconditionally after processing but before returning the stash.

See also the special meaning of the global toplevel variable.

Successive calls to process with the same Config::TT2 instance MUST be avoided. The Template CONTEXT and STASH have states belonging to the processed config text. Create new instances for successive process calls.

   $stash1 = Config::TT2->new->process($file1);
   $stash2 = Config::TT2->new->process($file2);

The following Template options are not supported with Config::TT2:

      PRE_PROCESS
      PROCESS
      POST_PROCESS
      WRAPPER
      AUTO_RESET
      DEFAULT
      OUTPUT
      OUTPUT_PATH
      ERROR
      ERRORS

EXTENSIONS AND VIRTUAL METHODS

With the context method you can get/set the underlying Template::Context object.

context()

Getter/setter method for the underlying Template::Context object.

With the context you can also access the stash and define new virtual methods BEFORE processing.

    $ctt2 = Config::TT2->new;
    $ctt2->context->stash->define_vmethod( $type, $name, $code_ref );
    $cfg_stash = $ctt2->process($cfg_file);

See the manuals Template::Stash, Template::Context and Template::Manual::Internals.

SEE ALSO

Config::Any::TT2, the corresponding Config::Any plugin.

Template::Manual::Intro, Template::Manual::Syntax, Template::Manual::Config, Template::Manual::Variables, Template::Manual::VMethods

AUTHOR

Karl Gaissmaier, <gaissmai at cpan.org>

BUGS

Please report any bugs or feature requests to bug-config-tt at rt.cpan.org, or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Config-TT2. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

SUPPORT

You can find documentation for this module with the perldoc command.

    perldoc Config::TT2

You can also look for information at:

LICENSE AND COPYRIGHT

Copyright 2012 Karl Gaissmaier.

This program is free software; you can redistribute it and/or modify it under the terms of either: the GNU General Public License as published by the Free Software Foundation; or the Artistic License.

See http://dev.perl.org/licenses/ for more information.