1PPI::Normal(3)        User Contributed Perl Documentation       PPI::Normal(3)
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NAME

6       PPI::Normal - Normalize Perl Documents
7
8   DESCRIPTION
9       Perl Documents, as created by PPI, are typically filled with all sorts
10       of mess such as whitespace and comments and other things that don't
11       effect the actual meaning of the code.
12
13       In addition, because there is more than one way to do most things, and
14       the syntax of Perl itself is quite flexible, there are many ways in
15       which the "same" code can look quite different.
16
17       PPI::Normal attempts to resolve this by providing a variety of
18       mechanisms and algorithms to "normalize" Perl Documents, and determine
19       a sort of base form for them (although this base form will be a memory
20       structure, and not something that can be turned back into Perl source
21       code).
22
23       The process itself is quite complex, and so for convenience and
24       extensibility it has been separated into a number of layers. At a later
25       point, it will be possible to write Plugin classes to insert additional
26       normalization steps into the various different layers.
27
28       In addition, you can choose to do the normalization only as deep as a
29       particular layer, depending on aggressively you want the normalization
30       process to be.
31

METHODS

33   register $function => $layer, ...
34       The "register" method is used by normalization method providers to tell
35       the normalization engines which functions need to be run, and in which
36       layer they apply.
37
38       Provide a set of key/value pairs, where the key is the full name of the
39       function (in string form), and the value is the layer (see description
40       of the layers above) in which it should be run.
41
42       Returns true if all functions are registered, or "undef" on error.
43
44   new
45         my $level_1 = PPI::Normal->new;
46         my $level_2 = PPI::Normal->new(2);
47
48       Creates a new normalization object, to which Document objects can be
49       passed to be normalized.
50
51       Of course, what you probably REALLY want is just to call
52       PPI::Document's "normalize" method.
53
54       Takes an optional single parameter of the normalisation layer to use,
55       which at this time can be either "1" or "2".
56
57       Returns a new "PPI::Normal" object, or "undef" on error.
58

layer

60       The "layer" accessor returns the normalisation layer of the object.
61
62   process
63       The "process" method takes anything that can be converted to a
64       PPI::Document (object, SCALAR ref, filename), loads it and applies the
65       normalisation process to the document.
66
67       Returns a PPI::Document::Normalized object, or "undef" on error.
68

NOTES

70       The following normalisation layers are implemented. When writing
71       plugins, you should register each transformation function with the
72       appropriate layer.
73
74   Layer 1 - Insignificant Data Removal
75       The basic step common to all normalization, layer 1 scans through the
76       Document and removes all whitespace, comments, POD, and anything else
77       that returns false for its "significant" method.
78
79       It also checks each Element and removes known-useless sub-element
80       metadata such as the Element's physical position in the file.
81
82   Layer 2 - Significant Element Removal
83       After the removal of the insignificant data, Layer 2 removed larger,
84       more complex, and superficially "significant" elements, that can be
85       removed for the purposes of normalisation.
86
87       Examples from this layer include pragmas, now-useless statement
88       separators (since the PDOM tree is holding statement elements), and
89       several other minor bits and pieces.
90
91   Layer 3 - TO BE COMPLETED
92       This version of the forward-port of the Perl::Compare functionality to
93       the 0.900+ API of PPI only implements Layer 1 and 2 at this time.
94

TO DO

96       - Write the other 4-5 layers :)
97

SUPPORT

99       See the support section in the main module.
100

AUTHOR

102       Adam Kennedy <adamk@cpan.org>
103
105       Copyright 2005 - 2011 Adam Kennedy.
106
107       This program is free software; you can redistribute it and/or modify it
108       under the same terms as Perl itself.
109
110       The full text of the license can be found in the LICENSE file included
111       with this module.
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115perl v5.38.0                      2023-09-22                    PPI::Normal(3)
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