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Code::Perl(3) User Contributed Perl Documentation Code::Perl(3)

Code::Perl - Produce Perl code from a tree

  use Code::Perl::Expr qw( :easy );

  my $c = derefh(scal('hash'), calls('getkey'));

  print $c->perl; # ($hash)->{getkey()}

Code::Perl allows you to build chunks of Perl code as a tree and then when you're finished building, the tree can output the Perl code. This is useful if you have built your own mini-language and you want to generate Perl from it. Rather than generating the Perl at parse time and having to worry about quoting, escaping, parenthese etc, you can just build a tree using Code::Perl and then dump out the correct Perl at the end.

All objects in Code::Perl conform to a basic interface. They all have a method "perl()" which when called returns a string of Perl code corresponding to the object. So for example

  my $s_i = Code::Perl::Expr::Scalar->new(Name => 'i');
  print $s_i->perl; # $i

  my $string = Code::Perl::Expr::String->new(Value => 'hello');
  print $string->perl; # "hello"

  my $list = Code::Perl::Expr::List(Value => [$s_i, $string]);
  print $list->perl; # $i, "hello"

  my $sub = Code::Perl::Expr::CallSub(SubName => "fn", Args => $list);
  print $sub->perl; # fn($i, "hello")

Expression types may also implement other methods but they vary from type to type, "perl()" is the only method that is mandatory.

Code::Perl is in development. There are no known bugs however it currently only has support for a limited range of operators, just enough to allow me to compile the TALES expression from Zope's TAL ( Hopefully this will allow Petal (a Perl implementation of TAL) to produce faster code.

See Code::Perl::Expr for details of the available expression types.

Code::Perl currently has no knowledge of operator precedence, so to be safe it uses parentheses even when they are not needed. The code is correct but it will be a little longer and less readable. It should have no impact on the efficience of the code produced.

Written by Fergal Daly <>.

Copyright 2003 by Fergal Daly <>.

This program is free software and comes with no warranty. It is distributed under the LGPL license

See the file LGPL included in this distribution or

2003-06-17 perl v5.32.1

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