.\" -*- mode: troff; coding: utf-8 -*-
.\" Automatically generated by Pod::Man 5.01 (Pod::Simple 3.43)
.\"
.\" Standard preamble:
.\" ========================================================================
.de Sp \" Vertical space (when we can't use .PP)
.if t .sp .5v
.if n .sp
..
.de Vb \" Begin verbatim text
.ft CW
.nf
.ne \\$1
..
.de Ve \" End verbatim text
.ft R
.fi
..
.\" \*(C` and \*(C' are quotes in nroff, nothing in troff, for use with C<>.
.ie n \{\
.    ds C` ""
.    ds C' ""
'br\}
.el\{\
.    ds C`
.    ds C'
'br\}
.\"
.\" Escape single quotes in literal strings from groff's Unicode transform.
.ie \n(.g .ds Aq \(aq
.el       .ds Aq '
.\"
.\" If the F register is >0, we'll generate index entries on stderr for
.\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index
.\" entries marked with X<> in POD.  Of course, you'll have to process the
.\" output yourself in some meaningful fashion.
.\"
.\" Avoid warning from groff about undefined register 'F'.
.de IX
..
.nr rF 0
.if \n(.g .if rF .nr rF 1
.if (\n(rF:(\n(.g==0)) \{\
.    if \nF \{\
.        de IX
.        tm Index:\\$1\t\\n%\t"\\$2"
..
.        if !\nF==2 \{\
.            nr % 0
.            nr F 2
.        \}
.    \}
.\}
.rr rF
.\" ========================================================================
.\"
.IX Title "PPIx::Utils::Traversal 3"
.TH PPIx::Utils::Traversal 3 2023-07-26 "perl v5.38.0" "User Contributed Perl Documentation"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH NAME
PPIx::Utils::Traversal \- Utility functions for traversing PPI documents
.SH SYNOPSIS
.IX Header "SYNOPSIS"
.Vb 1
\&    use PPIx::Utils::Traversal \*(Aq:all\*(Aq;
.Ve
.SH DESCRIPTION
.IX Header "DESCRIPTION"
This package is a component of PPIx::Utils that contains functions for
traversal of PPI documents.
.SH FUNCTIONS
.IX Header "FUNCTIONS"
All functions can be imported by name, or with the tag \f(CW\*(C`:all\*(C'\fR.
.SS first_arg
.IX Subsection "first_arg"
.Vb 1
\&    my $first_arg = first_arg($element);
.Ve
.PP
Given a PPI::Element that is presumed to be a function call (which
is usually a PPI::Token::Word), return the first argument.  This is
similar of "parse_arg_list" and follows the same logic.  Note that
for the code:
.PP
.Vb 1
\&    int($x + 0.5)
.Ve
.PP
this function will return just the \f(CW$x\fR, not the whole expression.
This is different from the behavior of "parse_arg_list".  Another
caveat is:
.PP
.Vb 1
\&    int(($x + $y) + 0.5)
.Ve
.PP
which returns \f(CW\*(C`($x + $y)\*(C'\fR as a PPI::Structure::List instance.
.SS parse_arg_list
.IX Subsection "parse_arg_list"
.Vb 1
\&    my @args = parse_arg_list($element);
.Ve
.PP
Given a PPI::Element that is presumed to be a function call (which
is usually a PPI::Token::Word), splits the argument expressions
into arrays of tokens.  Returns a list containing references to each
of those arrays.  This is useful because parentheses are optional when
calling a function, and PPI parses them very differently.  So this
method is a poor-man's parse tree of PPI nodes.  It's not bullet-proof
because it doesn't respect precedence. In general, I don't like the
way this function works, so don't count on it to be stable (or even
present).
.SS split_nodes_on_comma
.IX Subsection "split_nodes_on_comma"
.Vb 1
\&    my @args = split_nodes_on_comma(@nodes);
.Ve
.PP
This has the same return type as "parse_arg_list" but expects to be
passed the nodes that represent the interior of a list, like:
.PP
.Vb 1
\&    \*(Aqfoo\*(Aq, 1, 2, \*(Aqbar\*(Aq
.Ve
.SS get_next_element_in_same_simple_statement
.IX Subsection "get_next_element_in_same_simple_statement"
.Vb 1
\&    my $element = get_next_element_in_same_simple_statement($element);
.Ve
.PP
Given a PPI::Element, this subroutine returns the next element in
the same simple statement as defined by
"is_ppi_simple_statement" in PPIx::Utils::Classification. If no next
element can be found, this subroutine simply returns \f(CW\*(C`undef\*(C'\fR.
.PP
If the \f(CW$element\fR is undefined or unblessed, we simply return \f(CW\*(C`undef\*(C'\fR.
.PP
If the \f(CW$element\fR satisfies
"is_ppi_simple_statement" in PPIx::Utils::Classification, we return
\&\f(CW\*(C`undef\*(C'\fR, \fBunless\fR it has a parent which is a PPI::Structure::List.
.PP
If the \f(CW$element\fR is the last significant element in its PPI::Node,
we replace it with its parent and iterate again.
.PP
Otherwise, we return \f(CW\*(C`$element\->snext_sibling()\*(C'\fR.
.SS get_previous_module_used_on_same_line
.IX Subsection "get_previous_module_used_on_same_line"
.Vb 1
\&    my $element = get_previous_module_used_on_same_line($element);
.Ve
.PP
Given a PPI::Element, returns the PPI::Element representing the
name of the module included by the previous \f(CW\*(C`use\*(C'\fR or \f(CW\*(C`require\*(C'\fR on
the same line as the \f(CW$element\fR. If none is found, simply returns
\&\f(CW\*(C`undef\*(C'\fR.
.PP
For example, with the line
.PP
.Vb 1
\&    use version; our $VERSION = ...;
.Ve
.PP
given the PPI::Token::Symbol instance for \f(CW$VERSION\fR, this will
return "version".
.PP
If the given element is in a \f(CW\*(C`use\*(C'\fR or <require>, the return is from
the previous \f(CW\*(C`use\*(C'\fR or \f(CW\*(C`require\*(C'\fR on the line, if any.
.SS get_constant_name_elements_from_declaring_statement
.IX Subsection "get_constant_name_elements_from_declaring_statement"
.Vb 1
\&    my @constants = get_constant_name_elements_from_declaring_statement($statement);
.Ve
.PP
Given a PPI::Statement, if the statement is a Readonly, ReadonlyX, or
Const::Fast declaration statement or a \f(CW\*(C`use constant\*(C'\fR, returns the names
of the things being defined.
.PP
Given
.PP
.Vb 1
\&    use constant 1.16 FOO => \*(Aqbar\*(Aq;
.Ve
.PP
this will return the PPI::Token::Word containing \f(CW\*(AqFOO\*(Aq\fR.
Given
.PP
.Vb 1
\&    use constant 1.16 { FOO => \*(Aqbar\*(Aq, \*(AqBAZ\*(Aq => \*(Aqburfle\*(Aq };
.Ve
.PP
this will return a list of the PPI::Tokens containing \f(CW\*(AqFOO\*(Aq\fR and \f(CW\*(AqBAZ\*(Aq\fR.
Similarly, given
.PP
.Vb 1
\&    Readonly::Hash my %FOO => ( bar => \*(Aqbaz\*(Aq );
.Ve
.PP
or
.PP
.Vb 1
\&    const my %FOO => ( bar => \*(Aqbaz\*(Aq );
.Ve
.PP
this will return the PPI::Token::Symbol containing \f(CW\*(Aq%FOO\*(Aq\fR.
.SS split_ppi_node_by_namespace
.IX Subsection "split_ppi_node_by_namespace"
.Vb 1
\&    my $subtrees = split_ppi_node_by_namespace($node);
.Ve
.PP
Returns the sub-trees for each namespace in the node as a reference to a hash
of references to arrays of PPI::Nodes.  Say we've got the following code:
.PP
.Vb 1
\&    #!perl
\&
\&    my $x = blah();
\&
\&    package Foo;
\&
\&    my $y = blah_blah();
\&
\&    {
\&        say \*(AqWhee!\*(Aq;
\&
\&        package Bar;
\&
\&        something();
\&    }
\&
\&    thingy();
\&
\&    package Baz;
\&
\&    da_da_da();
\&
\&    package Foo;
\&
\&    foreach ( blrfl() ) {
\&        ...
\&    }
.Ve
.PP
Calling this function on a PPI::Document for the above returns a
value that looks like this, using multi-line string literals for the
actual code parts instead of PPI trees to make this easier to read:
.PP
.Vb 4
\&    {
\&        main    => [
\&            q<
\&                #!perl
\&
\&                my $x = blah();
\&            >,
\&        ],
\&        Foo     => [
\&            q<
\&                package Foo;
\&
\&                my $y = blah_blah();
\&
\&                {
\&                    say \*(AqWhee!\*(Aq;
\&
\&                }
\&
\&                thingy();
\&            >,
\&            q<
\&                package Foo;
\&
\&                foreach ( blrfl() ) {
\&                    ...
\&                }
\&            >,
\&        ],
\&        Bar     => [
\&            q<
\&                package Bar;
\&
\&                something();
\&            >,
\&        ],
\&        Baz     => [
\&            q<
\&                package Baz;
\&
\&                da_da_da();
\&            >,
\&        ],
\&    }
.Ve
.PP
Note that the return value contains copies of the original nodes, and not the
original nodes themselves due to the need to handle namespaces that are not
file-scoped.  (Notice how the first element for "Foo" above differs from the
original code.)
.SH BUGS
.IX Header "BUGS"
Report any issues on the public bugtracker.
.SH AUTHOR
.IX Header "AUTHOR"
Dan Book <dbook@cpan.org>
.PP
Code originally from Perl::Critic::Utils by Jeffrey Ryan Thalhammer
<jeff@imaginative\-software.com>, Perl::Critic::Utils::PPI and
PPIx::Utilities::Node by Elliot Shank <perl@galumph.com>, and
PPIx::Utilities::Statement by Thomas R. Wyant, III <wyant@cpan.org>
.SH "COPYRIGHT AND LICENSE"
.IX Header "COPYRIGHT AND LICENSE"
This software is copyright (c) 2005\-2011 Imaginative Software Systems,
2007\-2011 Elliot Shank, 2009\-2010 Thomas R. Wyant, III, 2017 Dan Book.
.PP
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
Perl::Critic::Utils, Perl::Critic::Utils::PPI, PPIx::Utilities