PPI::Normal(3) User Contributed Perl Documentation PPI::Normal(3)NAMEPPI::Normal - Normalize Perl Documents
DESCRIPTION
Perl Documents, as created by PPI, are typically filled with all sorts
of mess such as whitespace and comments and other things that don't
effect the actual meaning of the code.
In addition, because there is more than one way to do most things, and
the syntax of Perl itself is quite flexible, there are many ways in
which the "same" code can look quite different.
PPI::Normal attempts to resolve this by providing a variety of
mechanisms and algorithms to "normalize" Perl Documents, and determine
a sort of base form for them (although this base form will be a memory
structure, and not something that can be turned back into Perl source
code).
The process itself is quite complex, and so for convenience and
extensibility it has been separated into a number of layers. At a later
point, it will be possible to write Plugin classes to insert additional
normalization steps into the various different layers.
In addition, you can choose to do the normalization only as deep as a
particular layer, depending on aggressively you want the normalization
process to be.
METHODS
register $function => $layer, ...
The "register" method is used by normalization method providers to tell
the normalization engines which functions need to be run, and in which
layer they apply.
Provide a set of key/value pairs, where the key is the full name of the
function (in string form), and the value is the layer (see description
of the layers above) in which it should be run.
Returns true if all functions are registered, or "undef" on error.
new
my $level_1 = PPI::Normal->new;
my $level_2 = PPI::Normal->new(2);
Creates a new normalization object, to which Document objects can be
passed to be normalized.
Of course, what you probably REALLY want is just to call
PPI::Document's "normalize" method.
Takes an optional single parameter of the normalisation layer to use,
which at this time can be either "1" or "2".
Returns a new "PPI::Normal" object, or "undef" on error.
layer
The "layer" accessor returns the normalisation layer of the object.
process
The "process" method takes anything that can be converted to a
PPI::Document (object, SCALAR ref, filename), loads it and applies the
normalisation process to the document.
Returns a PPI::Document::Normalized object, or "undef" on error.
NOTES
The following normalisation layers are implemented. When writing
plugins, you should register each transformation function with the
appropriate layer.
Layer 1 - Insignificant Data Removal
The basic step common to all normalization, layer 1 scans through the
Document and removes all whitespace, comments, POD, and anything else
that returns false for its "significant" method.
It also checks each Element and removes known-useless sub-element
metadata such as the Element's physical position in the file.
Layer 2 - Significant Element Removal
After the removal of the insignificant data, Layer 2 removed larger,
more complex, and superficially "significant" elements, that can be
removed for the purposes of normalisation.
Examples from this layer include pragmas, now-useless statement
separators (since the PDOM tree is holding statement elements), and
several other minor bits and pieces.
Layer 3 - TO BE COMPLETED
This version of the forward-port of the Perl::Compare functionality to
the 0.900+ API of PPI only implements Layer 1 and 2 at this time.
TO DO
- Write the other 4-5 layers :)
SUPPORT
See the support section in the main module.
AUTHOR
Adam Kennedy <adamk@cpan.org>
COPYRIGHT
Copyright 2005 - 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.
perl v5.16.2 2011-02-25 PPI::Normal(3)
