Pod::Tree::Node - nodes in a Pod::Tree
$node = root Pod::Tree::Node \@paragraphs; $node = code Pod::Tree::Node $paragraph; $node = verbatim Pod::Tree::Node $paragraph; $node = command Pod::Tree::Node $paragraph; $node = ordinary Pod::Tree::Node $paragraph; $node = letter Pod::Tree::Node $token; $node = sequence Pod::Tree::Node $letter, \@children; $node = text Pod::Tree::Node $text; $node = target Pod::Tree::Node $target; $node = link Pod::Tree::Node $node, $page, $section; is_code $node and ... is_command $node and ... is_for $node and ... is_item $node and ... is_letter $node and ... is_list $node and ... is_ordinary $node and ... is_pod $node and ... is_root $node and ... is_sequence $node and ... is_text $node and ... is_verbatim $node and ... is_link $node and ... is_c_head1 $node and ... is_c_head2 $node and ... is_c_head3 $node and ... is_c_head4 $node and ... is_c_cut $node and ... is_c_pod $node and ... is_c_over $node and ... is_c_back $node and ... is_c_item $node and ... is_c_for $node and ... is_c_begin $node and ... is_c_end $node and ... $arg = get_arg $node; $brackets = get_brackets $node; $children = get_children $node; $command = get_command $node; $domain = get_domain $node; $item_type = get_item_type $node; $letter = get_letter $node; $list_type = get_list_type $node; $page = get_page $node; $raw = get_raw $node; $raw_kids = get_raw_kids $node; $section = get_section $node; $siblings = get_siblings $node; $target = get_target $node; $text = get_text $node; $type = get_type $node; $deep_text = get_deep_text $node; $node->force_text($text); $node->force_for; $node->parse_begin (\@nodes); $node->set_children(\@children); $node->make_sequences; $node->parse_links; $node->unescape; $node->consolidate; $node->make_lists; $node->clone; $node->dump; Pod::Tree::Node->set_filename($filename); $filename = $node->get_filename;
Pod::Escapes
Pod::Tree::Node objects are nodes in a tree that represents a POD. Applications walk the tree to recover the structure and content of the POD.
Pod::Tree::Node
Methods are provided for
creating nodes in the tree
parsing the POD into nodes
returning information about nodes
walking the tree
The tree descends from a single root node; is_root returns true on this node and no other.
is_root
$children = $root->get_children
returns a reference to an array of nodes. These nodes represent the POD.
For each node, call get_type to discover the type of the node
get_type
for $child (@$children) { $type = $child->get_type; }
$type will be one of these strings:
The node is the root of the tree.
The node represents a paragraph that is not part of the POD.
The node represents a verbatim paragraph.
The node represents an ordinary paragraph.
The node represents an =command paragraph (but not an =over paragraph).
The node represents an interior sequence.
The node represents the target of a link (An L<> markup).
The node represents text that contains no interior sequences.
The node represents an =over list.
The node represents an item in an =over list.
The node represents a =for paragraph, or it represents the paragraphs between =begin/=end commands.
Here are instructions for walking these node types.
Call
$children = $node->get_children
to get a list of nodes representing the POD.
A code node contains the text of a paragraph that is not part of the POD, for example, a paragraph that follows an =cut command. Call
=cut
$text = $node->get_text
to recover the text of the paragraph.
A verbatim node contains the text of a verbatim paragraph. Call
An ordinary node represents the text of an ordinary paragraph. The text is parsed into a list of text and sequence nodes; these nodes are the children of the ordinary node. Call
to get a list of the children. Iterate over this list to recover the text of the paragraph.
A command node represents an =command paragraph. Call
$command = $node->get_command;
to recover the name of the command. The name is returned without the equals sign.
=over paragraphs are represented by list nodes, not command nodes; see "list nodes", below.
The text of a command paragraph is parsed into a list of text and sequence nodes; these nodes are the children of the command node. Call
$children = $node->get_children;
A sequence node represents a single interior sequence (a <> markup). Call
$node->get_letter
to recover the original markup letter. The contents of the markup are parsed into a list of text and sequence nodes; these nodes are the children of the sequence node. Call
$node->get_children
to recover them.
Z<> and E<> markups do not generate sequence nodes; these markups are expanded by Pod::Tree when the tree is built.
Pod::Tree
If a sequence node represents a link (an L<> markup), then
L<>
is_link $node
returns true and
$target = $node->get_target
returns a node representing the target of the link.
Pod::Tree::Node can represent targets in two domains: POD and HTTP. The POD domain represents the
POD
HTTP
L<page/section>
markups that are described in perlpod. The HTTP domain represents L<> markups that contain a URL, e.g.
L<http://foo.bar.com/page.html#fragment>
$domain = $target->get_domain
to discover the domain of the target. For targets in the POD domain, call
$page = $target->get_page; $section = $target->get_section;
to recover the man page and section that the link refers to. For targets in the HTTP domain, call
$url = $target->get_page;
to recover the URL for the link.
$target is used only for constructing hyper-links; the text to be displayed for the link is recovered by walking the children of $node, as for any other interior sequence.
A text node represents text that contains no interior sequences. Call
to recover the text.
A list node represents an =over list. Call
$list_type = $node->get_list_type;
to discover the type of the list. This will be one of the strings
The type of a list is the type of the first item in the list.
The children of a list node are item nodes; each item node represents one item in the list.
You can call
$node->get_arg;
to recover the indent value following the =over.
An item node represents one item in an =over list. Call
$item_type = $node->get_item_type;
to discover the type of the item. This will be one of the strings shown above for "list nodes". Typically, all the items in a list have the same type, but Pod::Tree::Node doesn't assume this.
The children of an item node represent the text of the =item paragraph; this is usually of interest only for 'text' items. Call
to get a list of the children; these will be sequence and text nodes, as for any other =command paragraph.
Each item node also has a list of nodes representing all the paragraphs following it, up to the next =item command, or the end of the list. These nodes are called siblings of the item node. Call
$siblings = $node->get_siblings
to get a list of sibling nodes.
for nodes represent text that is to be passed to an external formatter. Call
$formatter = $node->get_arg;
to discover the name of the formatter. Call
$text = $node->get_text;
to obtain the text to be passed to the formatter. This will either be the text of an =for command, or all of the text between =begin and =end commands.
PODs have a recursive structure; therefore, any application that walks a Pod::Tree must also be recursive. See skeleton for an example of the necessary code.
These methods construct Pod::Tree::Node objects. They are used to build trees. They aren't necessary to walk trees.
$node = root Pod::Tree::Node \@paragraphs; $node = code Pod::Tree::Node $paragraph; $node = verbatim Pod::Tree::Node $paragraph; $node = command Pod::Tree::Node $paragraph; $node = ordinary Pod::Tree::Node $paragraph; $node = letter Pod::Tree::Node $token; $node = sequence Pod::Tree::Node $letter, \@children; $node = text Pod::Tree::Node $text; $node = target Pod::Tree::Node $target; $node = link Pod::Tree::Node $node, $page, $section;
link
Creates a new sequence node representing an L<> markup. $node becomes the sole child of the new node. The target of the node is constructed from $page and $section.
This method isn't used to parse PODs. It is provided for applications that want to create new links in an existing Pod::Tree structure.
These methods return true iff $node has the type indicated by the method name.
is_code $node and ... is_command $node and ... is_for $node and ... is_item $node and ... is_letter $node and ... is_link $node and ... is_list $node and ... is_ordinary $node and ... is_pod $node and ... is_root $node and ... is_sequence $node and ... is_text $node and ... is_verbatim $node and ...
is_pod returns true for all nodes except code, =pod, and =cut nodes.
is_pod
=pod
These methods return true iff $node is a command node, and the command is the one indicated by the method name.
is_c_head1 $node and ... is_c_head2 $node and ... is_c_head3 $node and ... is_c_head4 $node and ... is_c_cut $node and ... is_c_pod $node and ... is_c_over $node and ... is_c_back $node and ... is_c_item $node and ... is_c_for $node and ... is_c_begin $node and ... is_c_end $node and ...
These methods return information about nodes. Most accessors are only relevant for certain types of nodes.
get_arg
Returns the argument of $node. This is the number following an =over command, or the name of an external translator for =for, =begin, and =end commands. Only relevant for these four command nodes.
get_brackets
Only relevant for for nodes.
If the node represents an =for command, @$brackets is a single-element list. The list element is the text of the =for command and its argument, i.e. the name of the external formatter.
If the node represents a =begin/=end construct, @$brackets is a two-element list containing the text of the =begin and =end paragraphs.
get_children
Returns a reference to the list of nodes that are children of $node. May be called on any node. The list may be empty.
get_command
Returns the name of a command, without the equals sign. Only relevant for command nodes.
get_domain
Only relevant for target nodes. Returns the domain of the target. This will be one of the strings
get_item_type
Returns the type of an item node. The type will be one of
get_letter
Returns the letter that introduces an interior sequence. Only relevant for sequence nodes.
get_list_type
Returns the type of a list node. The type of a list node is the type of the first item node in the list.
get_page
Only relevant for target nodes. For targets in the POD domain, returns the man page that is the target of the link. For targets in the HTTP domain, returns the URL that is the target of the link.
get_raw
Returns the original text of a paragraph. Currently provided for command, verbatim, and ordinary paragraphs.
get_raw_kids
Only provided for L<> sequence nodes. Returns a reference to a list of nodes representing the entire text of the L<> sequence, including any part following a vertical bar (|).
The original text of the L<> markup can be reconstructed from this list.
get_section
Only relevant for target nodes in the POD domain. Returns the section that is the target of a link.
get_siblings
Returns the siblings of a node. May be called on any node. Only item nodes have siblings.
get_target
Returns the target of a node. Only relevant for sequence nodes that represent links (L<> markups). is_link returns true on these nodes.
is_link
get_text
Returns the text of a node. $text will not contain any interior sequences. Only relevant for text nodes.
Returns the type of $node. May be called on any node. See "TREE STRUCTURE" for descriptions of the node types.
get_deep_text
Recursively walks the children of a node, catenates together the text from each node, and returns all that text as a single string. All interior sequence markups are discarded.
get_deep_text is provided as a convenience for applications that want to ignore markups in a POD paragraph.
These methods manipulate the tree while it is being built. They aren't necessary to walk the tree.
$node->force_text($text) $node->force_for; $node->parse_begin (\@nodes); $node->set_children(\@children); $node->make_sequences; $node->parse_links; $node->unescape; $node->consolidate; $node->make_lists;
clone
Returns a deep copy of a node. Only implemented for text and sequence nodes.
text
sequence
dump
Returns a string containing a pretty-printed representation of the node. Calling dump on the root node of a tree will show the entire POD.
set_filename
Sets the file name to be reported in error messages.
getfile_name
Returns the file name set by set_file_name.
set_file_name
The t/ directory in the Pod::Tree distribution contains examples of PODs, together with dumps of the trees that Pod::Tree constructs for them. The tree for t/file.pod is in t/file.p_exp.
t/
.pod
.p_exp
Pod::Tree::Node::dump is a simple example of code that walks a POD tree.
Pod::Tree::Node::dump
skeleton is a skeleton application that walks a POD tree.
There is no provision in perlpod for L<> markups to contain URLs, but due to popular demand, this is now supported in Pod::Tree::Node.
perl(1), Pod::Tree
Steven McDougall, swmcd@world.std.com
Copyright (c) 1999-2004 by Steven McDougall. This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
To install Pod::Tree, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Pod::Tree
CPAN shell
perl -MCPAN -e shell install Pod::Tree
For more information on module installation, please visit the detailed CPAN module installation guide.