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PPI::Token::HereDoc(3)               User Contributed Perl Documentation              PPI::Token::HereDoc(3)



NAME
       PPI::Token::HereDoc - Token class for the here-doc

INHERITANCE
         PPI::Token::HereDoc
         isa PPI::Token
             isa PPI::Element

DESCRIPTION
       Here-docs are incredibly handy when writing Perl, but incredibly tricky when parsing it, primarily
       because they don't follow the general flow of input.

       They jump ahead and nab lines directly off the input buffer. Whitespace and newlines may not matter
       in most Perl code, but they matter in here-docs.

       They are also tricky to store as an object. They look sort of like an operator and a string, but they
       don't act like it. And they have a second section that should be something like a separate token, but
       isn't because a strong can span from above the here-doc content to below it.

       So when parsing, this is what we do.

       Firstly, the PPI::Token::HereDoc object, does not represent the "<<" operator, or the "END_FLAG", or
       the content, or even the terminator.

       It represents all of them at once.

       The token itself has only the declaration part as its "content".

         # This is what the content of a HereDoc token is
         <<FOO

         # Or this
         <<"FOO"

         # Or even this
         <<      'FOO'

       That is, the "operator", any whitespace separator, and the quoted or bare terminator. So when you
       call the "content" method on a HereDoc token, you get '<< "FOO"'.

       As for the content and the terminator, when treated purely in "content" terms they do not exist.

       The content is made available with the "heredoc" method, and the name of the terminator with the
       "terminator" method.

       To make things work in the way you expect, PPI has to play some games when doing line/column location
       calculation for tokens, and also during the content parsing and generation processes.

       Documents cannot simply by recreated by stitching together the token contents, and involve a somewhat
       more expensive procedure, but the extra expense should be relatively negligible unless you are doing
       huge quantities of them.

       Please note that due to the immature nature of PPI in general, we expect "HereDocs" to be a rich
       (bad) source of corner-case bugs for quite a while, but for the most part they should more or less
       DWYM.

   Comparison to other string types
       Although technically it can be considered a quote, for the time being "HereDocs" are being treated as
       a completely separate "Token" subclass, and will not be found in a search for PPI::Token::Quote or
       "PPI::Token::QuoteLike objects".

       This may change in the future, with it most likely to end up under QuoteLike.

METHODS
       Although it has the standard set of "Token" methods, "HereDoc" objects have a relatively large number
       of unique methods all of their own.

   heredoc
       The "heredoc" method is the authoritative method for accessing the contents of the "HereDoc" object.

       It returns the contents of the here-doc as a list of newline-terminated strings. If called in scalar
       context, it returns the number of lines in the here-doc, excluding the terminator line.

   terminator
       The "terminator" method returns the name of the terminating string for the here-doc.

       Returns the terminating string as an unescaped string (in the rare case the terminator has an escaped
       quote in it).

TO DO
       - Implement PPI::Token::Quote interface compatibility

       - Check CPAN for any use of the null here-doc or here-doc-in-s///e

       - Add support for the null here-doc

       - Add support for here-doc in s///e

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.



perl v5.16.2                                     2011-02-25                           PPI::Token::HereDoc(3)