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

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

	 isa PPI::Token
	     isa PPI::Element

       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-

       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 string 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

	 # Or this

	 # 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

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

       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.

       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).

       - 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

       See the support section in the main module.

       Adam Kennedy <>

       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 v5.32.1			  2019-07-09		PPI::Token::HereDoc(3)


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