PPI::Lexer(3) The PPI Lexer


use PPI;

# Create a new Lexer
my $Lexer = PPI::Lexer->new;

# Build a PPI::Document object from a Token stream
my $Tokenizer = PPI::Tokenizer->load('My/Module.pm');
my $Document = $Lexer->lex_tokenizer($Tokenizer);

# Build a PPI::Document object for some raw source
my $source = "print 'Hello World!'; kill(Humans->all);";
$Document = $Lexer->lex_source($source);

# Build a PPI::Document object for a particular file name
$Document = $Lexer->lex_file('My/Module.pm');


The is the PPI Lexer. In the larger scheme of things, its job is to take token streams, in a variety of forms, and ``lex'' them into nested structures.

Pretty much everything in this module happens behind the scenes at this point. In fact, at the moment you don't really need to instantiate the lexer at all, the three main methods will auto-instantiate themselves a "PPI::Lexer" object as needed.

All methods do a one-shot "lex this and give me a PPI::Document object".

In fact, if you are reading this, what you probably want to do is to just ``load a document'', in which case you can do this in a much more direct and concise manner with one of the following.

  use PPI;
  $Document = PPI::Document->load( $filename );
  $Document = PPI::Document->new( $string );

See PPI::Document for more details.

For more unusual tasks, by all means forge onwards.



The "new" constructor creates a new "PPI::Lexer" object. The object itself is merely used to hold various buffers and state data during the lexing process, and holds no significant data between ->lex_xxxxx calls.

Returns a new "PPI::Lexer" object

lex_file $filename

The "lex_file" method takes a filename as argument. It then loads the file, creates a PPI::Tokenizer for the content and lexes the token stream produced by the tokenizer. Basically, a sort of all-in-one method for getting a PPI::Document object from a file name.

Returns a PPI::Document object, or "undef" on error.

lex_source $string

The "lex_source" method takes a normal scalar string as argument. It creates a PPI::Tokenizer object for the string, and then lexes the resulting token stream.

Returns a PPI::Document object, or "undef" on error.

lex_tokenizer $Tokenizer

The "lex_tokenizer" takes as argument a PPI::Tokenizer object. It lexes the token stream from the tokenizer into a PPI::Document object.

Returns a PPI::Document object, or "undef" on error.


For any error that occurs, you can use the "errstr", as either a static or object method, to access the error message.

If no error occurs for any particular action, "errstr" will return false.


- Add optional support for some of the more common source filters

- Some additional checks for blessing things into various Statement and Structure subclasses.


See the support section in the main module.


Adam Kennedy <[email protected]>


Copyright 2001 - 2011 Adam Kennedy.

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

The full text of the license can be found in the LICENSE file included with this module.