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Acme::MetaSyntactic - Themed metasyntactic variables names


    use Acme::MetaSyntactic; # loads the default theme
    print metaname();

    # this sets the default theme and loads Acme::MetaSyntactic::shadok
    my $meta = Acme::MetaSyntactic->new( 'shadok' );

    print $meta->name();          # return a single name
    my @names = $meta->name( 4 ); # return 4 distinct names (if possible)

    # you can temporarily switch theme
    # (though it shifts your metasyntactical paradigm in other directions)
    my $foo = $meta->name( 'foo' );       # return 1 name from theme foo
    my @foo = $meta->name( toto => 2 );   # return 2 names from theme toto

    # but why would you need an instance variable?
    use Acme::MetaSyntactic qw( batman robin );

    # the first loaded theme is the default (here batman)
    print metaname;
    my @names = metaname( 4 );

    print join ',', metabatman(3), metarobin;

    # the convenience functions are only exported
    # - via the Acme::MetaSyntactic import list
    # - when an individual theme is used
    print join $/, metabatman( 5 );

    use Acme::MetaSyntactic::donmartin;
    print join $/, metadonmartin( 7 );

    # but a one-liner is even better
    perl -MAcme::MetaSyntactic=batman -le 'print metaname'

    # the meta(1) command-line tool can be helpful too
    meta batman


When writing code examples, it's always easy at the beginning:

    my $foo = "bar";
    $foo .= "baz";   # barbaz

But one gets quickly stuck with the same old boring examples. Does it have to be this way? I say "No".

Here is Acme::MetaSyntactic, designed to fulfill your metasyntactic needs. Never again will you scratch your head in search of a good variable name!


Acme::MetaSyntactic has an object-oriented interface, but can also export a few functions (see EXPORTS).


If you choose to use the OO interface, the following methods are available:

new( $theme )

Create a new instance of Acme::MetaSyntactic with the theme $theme. If $theme is omitted, the default theme is foo.

name( [ $theme, ] $count )

Return $count items from theme $theme. If no theme is given, the theme is the one passed to the constructor.

If $count is omitted, it defaults to 1.

If $count is 0, the whole list is returned (this may vary depending on the "behaviour" of the theme) in list context, and the size of the list in scalar context.

There are also some class methods:

themes( )

Return the sorted list of all available themes.

has_theme( $theme )

Return true if the theme $theme exists.

add_theme( theme => [ @items ], ... )

This class method adds a new theme to the list. It also creates and exports all the convenience functions (metatheme()) needed.

Note that this method can only create themes that implement the Acme::MetaSyntactic::List behaviour.

load_data( $data )

This method is used by the "behaviour" classes (such as Acme::MetaSyntactic::List) to read the content of the DATA filehandle and fetch the theme data.

The format is very simple. If the DATA filehandle contains the following data:

    # names
    bam zowie plonk
    powie kapow # comment
    # multi level
      abc    def
    # empty
    # multi lingual
    fr de

load_data() will return the following data structure (the string is trimmed, newlines and duplicate whitespace characters are squashed, and end-of-line comments are removed):

        names => "bam zowie plonk powie kapow",
        multi => {
            level   => "abc def",
            lingual => "fr de",
        empty => ""

For example, Acme::MetaSyntactic::List uses the single parameter names to fetch the lists of names for creating its subclasses.

The init() method in all "behaviour" classes will also accept an optional $data hashref and if it provided, will use it instead of reading the __DATA__ section of the module. The actual structure of the hashref depends on the Acme::MetaSyntactic:: class.

Convenience methods also exists for all the themes. The methods are named after the theme. They are exported only when the theme is actually used or when it appear in the Acme::MetaSyntactic import list. The first imported theme is the default, used by the metaname() function.


Depending on how Acme::MetaSyntactic is used, several functions can be exported. All of them behave like the following:

metaname( [ $theme, ] $count )

Return $count items from theme $theme. If no theme is given, the theme is "default" theme. See below how to change what the default is.

Use cases

use Acme::MetaSyntactic;

This exports the metaname() function only.

use Acme::MetaSyntactic 'theme';

This exports the metaname() function and the metatheme() function. metaname() default to the theme theme.

use Acme::MetaSyntactic qw(theme1 theme2);

This exports the metaname(), metatheme1(), metatheme2() functions. metaname() default to the first theme of the list (theme1).

use Acme::MetaSyntactic ':all';

This exports the metaname() function and the meta* functions for all themes. metaname() default to the standard default theme (foo).

use Acme::MetaSyntactic::theme;

This exports the metatheme() function only. The metaname() function is not exported.


The list of available themes can be obtained with the following one-liner:

    $ perl -MAcme::MetaSyntactic -le 'print for Acme::MetaSyntactic->themes'

The themes are all the Acme::MetaSyntactic::theme classes, with theme starting with a lowercase letter.

The items that make up Acme::MetaSyntactic themes are finite lists of valid Perl identifiers (not the UTF-8 kind).

Theme behaviours

Acme::MetaSyntactic provides theme authors with the capability of creating theme "behaviours". Behaviours are implemented as classes from which the individual themes inherit.

The behaviours are all the Acme::MetaSyntactic::type classes, with type starting with an uppercase letter.

Here are the available behaviours:


The theme is a simple collection of names. An object instance will return names at random from the list, and not repeat any until the list is exhausted.


The theme is made of several collections of names, each associated with a "language". The language is either passed as a constructor parameter, extracted from the environment or a default is selected.


The theme is made of several collections of names, each associated with a "category". Categories can include sub-categories, etc, ad infinitum (or when disk space or memory is exhausted, whichever happens first). The category is either passed as a constructor parameter or the default value is selected.


The theme is simply an alias of another theme. All items are identical, as the original behaviour. The only difference is the theme name.

Over time, new theme "behaviours" will be added.


Acme::MetaSyntactic::Themes, meta, metafy.


Philippe 'BooK' Bruhat, <>


Please report any bugs or feature requests to, or through the web interface at I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

If you think this modules lacks a particular set of metasyntactic variables, please send me a list, as well as a generation algorithm (either one of the built-ins (Acme::MetaSyntactic::List, Acme::MetaSyntactic::Locale), or a new one of your invention).


Individual contributors are listed in the individual theme files. Look at the included CONTRIBUTORS file for the list of all contributors (43 in this version).

However, this module could not have been possible without:

  • Some sillyness

    See, the follow-up, and the announce

  • The Batman serial from the 60s (it was shown in France in the 80s).

    my wife loves it, I name most of my machines after the bat fight sound effects (zowie, klonk, zlonk), and I even own a CD of the serial's theme music and the DVD of the movie (featuring the batboat and the batcopter!).

  • Rafael Garcia-Suarez,

    who apparently plans to use it. Especially now that it's usable in one-liners.

  • Vahe Sarkissian,

    who was the first to suggest an additional list (the sound effects from Don Martin's comic-books) and provided a link to a comprehensive list.

  • Sébastien Aperghis-Tramoni,

    who actually uses it, to do what he thinks is the only logical thing to do with Acme::MetaSyntactic: an IRC bot! See Bot::MetaSyntactic.

        #perlfr Sat Mar  5 01:15 CET 2005
        <Maddingue> BooK: bon, l'API de AMS, tu l'as changé alors ?
        <BooK> je sais pas
        <Maddingue> comment on fait pour invoquer ton merder
        <BooK> ca se mélange dans ma tete
        <BooK> je peux te montrer des use case
        <Maddingue> je veux juste savoir si tu vas changer la commande meta
        <Maddingue> BooK: parce que j'ai fais la seule chose qui me semblait
                    logique de faire avec ton module
        <BooK> un robot irc
  • Jérôme Fenal,

    who wrote Acme::MetaSyntactic::RefactorCode, which helps Acme::MetaSyntactic fulfill its role: rename your boring variables with silly names.

  • Abigail,

    who provided by himself more than 35 themes (I stopped counting after that). I probably won't be able to include them all before version 1.00.


Copyright 2005-2017 Philippe 'BooK' Bruhat, All Rights Reserved.


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