NAME¶
PPI::Transform - Abstract base class for document transformation classes
DESCRIPTION¶
"PPI::Transform" provides an API for the creation of classes and
objects that modify or transform PPI documents.
METHODS¶
new¶
my $transform = PPI::Transform->new(
param1 => 'value1',
param2 => 'value2',
);
The "new" constructor creates a new object for your
"PPI::Transform" subclass. A default constructor is provided for you
which takes no params and creates a basic, empty, object.
If you wish to have your transform constructor take params, these
must be
in the form of a list of key/value pairs.
Returns a new "PPI::Transform"-compatible object, or returns
"undef" on error.
document¶
The "document" method should be implemented by each subclass, and
takes a single argument of a PPI::Document object, modifying it
in
place as appropriate for the particular transform class.
That's right, this method
will not clone and
should not clone the
document object. If you do not want the original to be modified, you need to
clone it yourself before passing it in.
Returns the numbers of changes made to the document. If the transform is unable
to track the quantity (including the situation where it cannot tell
IF
it made a change) it should return 1. Returns zero if no changes were made to
the document, or "undef" if an error occurs.
By default this error is likely to only mean that you passed in something that
wasn't a PPI::Document, but may include additional errors depending on the
subclass.
apply¶
The "apply" method is used to apply the transform to something. The
argument must be a PPI::Document, or something which can be turned into a one
and then be written back to again.
Currently, this list is limited to a "SCALAR" reference, although a
handler registration process is available for you to add support for
additional types of object should you wish (see the source for this module).
Returns true if the transform was applied, false if there is an error in the
transform process, or may die if there is a critical error in the apply
handler.
file¶
# Read from one file and write to another
$transform->file( 'Input.pm' => 'Output.pm' );
# Change a file in place
$transform->file( 'Change.pm' );
The "file" method modifies a Perl document by filename. If passed a
single parameter, it modifies the file in-place. If provided a second
parameter, it will attempt to save the modified file to the alternative
filename.
Returns true on success, or "undef" on error.
SUPPORT¶
See the support section in the main module.
AUTHOR¶
Adam Kennedy <adamk@cpan.org>
COPYRIGHT¶
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.