NAME

Language::Expr::Compiler::JS - Compile Language::Expr expression to JavaScript

VERSION

version 0.21

SYNOPSIS

 use Language::Expr::Compiler::JS;
 my $jsc = Language::Expr::Compiler::JS->new;
 print $jsc->js('map({$_**2}, [1, 2, 3])'); # prints: [1, 2, 3].map(function(_){ Math.pow(_, 2) })

 # map Expr function to JS function/method/property
 $jsc->func_mapping->{ceil} = 'Math.ceil';
 $jsc->func_mapping->{uc} = '.toUpperCase';
 $jsc->func_mapping->{length} = ':length';
 print $jsc->js(q{uc("party like it's ") . ceil(1998.9)}); # prints: "party like it's ".toUpperCase() + Math.ceil(1998.9)

DESCRIPTION

Compiles Language::Expr expression to JavaScript code. Some notes:

• JavaScript version

  This compiler emits JavaScript 1.8.1 code (it uses several Array methods like map() and filter() [supported since JavaScript 1.6], 'let' lexical variables [supported since JavaScript 1.7 / Firefox 2] and native JSON [supported since JavaScript 1.8.1 / Firefox 3.5]).

  Currently to test emitted JavaScript code, we use Spidermonkey 1.9.1+ JavaScript interpreter (typically located in /usr/bin/js) as the JavaScript and JE modules are still not up to par.

• JavaScript-ness

  The emitted JS code will follow JavaScript's weak typing and coercion rules, e.g. Expr '1+"2"' will simply be translated to JavaScript '1+"2"' and will result in "12".

• Variables by default simply use JavaScript variables.

  E.g. $a becomes a, and so on. Be careful not to make variables which are invalid in JavaScript, e.g. $.. or ${foo/bar}.

  You can customize this behaviour by subclassing rule_var() or by providing a hook_var() (see documentation in Language::Expr::Compiler::Base).

• Functions by default simply use Javascript functions.

  Except those mentioned in func_mapping (e.g. rand() becomes Math.rand() if func_mapping->{rand} is 'Math.rand'). You can also map to JavaScript method (using '.meth' syntax) and property (using ':prop' syntax).

  You can customize this behaviour by subclassing rule_func() or by providing a hook_func() (see documentation in Language::Expr::Compiler::Base).

METHODS

js($expr) => $js_code

Convert Language::Expr expression into JavaScript code. Dies if there is syntax error in expression.

AUTHOR

Steven Haryanto <stevenharyanto@gmail.com>

COPYRIGHT AND LICENSE

This software is copyright (c) 2013 by Steven Haryanto.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.