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Pod::Tree::HTML(3) |
User Contributed Perl Documentation |
Pod::Tree::HTML(3) |
Pod::Tree::HTML - Generate HTML from a Pod::Tree
use Pod::Tree::HTML;
$source = Pod::Tree->new(%options);
$source = "file.pod";
$source = IO::File->new;
$source = \$pod;
$source = \@pod;
$dest = HTML::Stream->new;
$dest = IO::File->new;
$dest = "file.html";
$html = Pod::Tree::HTML->new($source, $dest, %options);
$html->set_options(%options);
@values = $html->get_options(@keys);
$html->translate;
$html->translate($template);
$html->emit_toc;
$html->emit_body;
$fragment = $html->escape_2396 ($section);
$url = $html->assemble_url($base, $page, $fragment);
"HTML::Stream",
"Text::Template"
"Pod::Tree::HTML" reads a POD and translates
it to HTML. The source and destination are fixed when the object is created.
Options are provided for controlling details of the translation.
The "translate" method does the
actual translation.
For convenience,
"Pod::Tree::HTML" can read PODs from a
variety of sources, and write HTML to a variety of destinations. The
"new" method resolves the
$source and $dest arguments.
"Pod::Tree::HTML" can also use
"Text::Template" to fill in an HTML
template file.
"Pod::Tree::HTML" can obtain a POD from any of
5 sources. "new" resolves
$source by checking these things, in order:
- 1.
- If $source "isa"
"POD::Tree", then the POD is taken from
that tree.
- 2.
- If $source is not a reference, then it is taken to be
the name of a file containing a POD.
- 3.
- If $source "isa"
"IO::File", then it is taken to be an
"IO::File" object that is already open
on a file containing a POD.
- 4.
- If $source is a SCALAR reference, then the text of
the POD is taken from that scalar.
- 5.
- if $source is an ARRAY reference, then the paragraphs
of the POD are taken from that array.
If $source isn't any of these things,
"new"
"die"s.
"Pod::Tree::HTML" can write HTML to any of 5
destinations. "new" resolves
$dest by checking these things, in order:
- 1.
- If $dest "isa"
"HTML::Stream", then
"Pod::Tree::HTML" writes HTML to that
stream.
- 2.
- If $dest "isa"
"IO::File", then
"Pod::Tree::HTML" writes HTML to that
file.
- 3.
- If $dest has a
"print" method, then
"Pod::Tree::HTML" passes HTML to that
method.
- 4.
- If $dest is a SCALAR reference, then
"Pod::Tree::HTML" writes HTML to that
scalar.
- 5.
- If $dest is a string, then
"Pod::Tree::HTML" writes HTML to the
file with that name.
If $dest isn't any of these things,
"new"
"die"s.
- $html = "new" "Pod::Tree::HTML"
$source, $dest,
%options
- Creates a new "Pod::Tree::HTML" object.
$html reads a POD from
$source , and writes HTML to
$dest. See "Source resolution" and
"Destination resolution" for details.
Options controlling the translation may be passed in the
%options hash. See "OPTIONS" for
details.
- $html->"set_options"(%options)
- Sets options controlling the translation. See "OPTIONS" for
details.
- @values =
$html->"get_options"(@keys)
- Returns the current values of the options specified in
@keys. See "OPTIONS" for details.
- $html->"translate"
- $html->"translate"($template)
- Translates the POD to HTML. This method should only be called once.
In the second form, $template is the name
of a file containing a template. The template will be filled in by the
"Text::Template" module. Here is a
minimal template, showing example usage of all the variables that are
set by "Pod::Tree::HTML".
<html>
<head>
<base href="{$base}">
<link href="{$css}" rel="stylesheet" type="text/css">
<title>{$title}</title>
</head>
<body bgcolor="{$bgcolor}" text="{$text}">
{$toc}
{$body}
</body>
</html>
The program fragments in the template are evaulted in the
"Pod::Tree::HTML" package. Any
variables that you set in this package will be available to your
template.
When a template is used, the destination must not be an
"HTML::Stream" object.
"translate" doesn't return
anything. The first form always returns. The second form
"die"s if there is an error creating
or filling in the template.
- $html->"emit_toc"
- $html->"emit_body"
- Emits the table of contents and body of the HTML document.
These methods are called automatically by
"translate". They are exposed in the
API for applications that wish to embed the HTML inside a larger
document.
These methods are provided for implementors who write their own link mapper
objects.
- $fragment =
$html->"escape_2396"($section)
- Escapes $section according to RFC 2396. For example,
the section
some section
is returned as
some%20section
- $url =
$html->"assemble_url"($base,
$page, $fragment)
- Assembles $base, $page, and
$fragment into a URL, of the form
$base/$page#$fragment
Attempts to construct a valid URL, even if some of
$base, $page, and
$fragment are empty.
- "base" => $url
- Specifies a base URL for relative HTML links.
- "bgcolor" => #rrggbb
- Set the background color to #rrggbb. Default is white.
- "css" => $url
- Specifies a Cascading Style Sheet for the generated HTML page.
- "depth" => $depth
- Specifies the depth of the generated HTML page in a directory tree. See
"LINK MAPPING" for details.
- "empty" => 1
- Causes the "translate" method to emit an
HTML file, even if the POD is empty. If this option is not provided, then
no HTML file is created for empty PODs.
- "hr" => $level
- Controls the profusion of horizontal lines in the output, as follows:
$level horizontal lines
0 none
1 between TOC and body
2 after each =head1
3 after each =head1 and =head2
Default is level 1.
- "link_map" => $link_map
- Sets the link mapper. See "LINK MAPPING" for details.
- "text" => #rrggbb
- Set the text color to #rrggbb. Default is black.
- "title" => title
- Set the page title to title. If no
"title" option is given,
"Pod::Tree::HTML" will attempt construct
a title from the second paragrah of the POD. This supports the following
style:
=head1 NAME
ls - list contents of directory
- "toc" => [0|1]
- Includes or omits the table of contents. Default is to include the
TOC.
"Pod::Tree::HTML" automatically generates HTML
destination anchors for all =headn command paragraphs, and for text
items in =over lists. The text of the paragraph becomes the
"name" attribute of the anchor. Markups are
ignored and the text is escaped according to RFC 2396.
For example, the paragraph
=head1 C<Foo> Bar
is translated to
<h1><a name="Foo%20Bar"><code>Foo</code> Bar</a></h1>
To link to a heading, simply give the text of the heading in an
"L<>" markup. The text must match
exactly; markups may vary. Either of these would link to the heading shown
above
L</C<Foo> Bar>
L</Foo Bar>
To generate destination anchors in other places, use the index
("X<>") markup
We can link to X<this text> this text.
and link to it as usual
L</this text> uses the index markup.
Earlier versions of this module also emitted the content of the
X<> markup as visible text. However, perlpod now specifies that
X<> markups render as an empty string, so
"Pod::Tree::HTML" has been changed to do
that.
The POD specification provides the "L<>"
markup to link from one document to another. HTML provides anchors
("<a href=""></a>")
for the same purpose. Obviously, a POD2HTML translator should convert the
first to the second.
In general, this is a hard problem. In particular, the POD format
is not powerful enough to support the kind of hyper-linking that people want
in a complex documentation system.
Rather than try to be all things to all people,
"Pod::Tree::HTML" uses a link
mapper object to translate the target of a POD link to a URL. The
default link mapper does a simple translation, described below. If you don't
like the default translation, you can provide your own link mapper with the
""link_map" =>
$link_map " option.
The default link mapper obtains the page and section from the
target. It translates "::" sequences in the
page to "/", and returns a URL of the
form
["../"...][page".html"]["#"section]
If the ""depth" =>
$depth" option is given, a corresponding number
of "../" sequences are prepended to
page.
This is a relative URL, so it will be interpreted relative to the
""base" =>
$url" option, if any.
To use your own link mapper, create a link mapper object and provide it to
"Pod::Tree::HTML" with the
"link_map" option
sub MyMapper::new { bless {}, shift }
sub MyMapper::url
{
my($mapper, $html, $target) = @_;
...
return $url;
}
$mapper = MyMapper->new;
$html = Pod::Tree::HTML->new(link_map => $mapper);
Your object should implement one method
- $url =
$mapper->"url"($html,
$target)
- When
$html->"translate"()
encounters an "L<>" markup, it
calls
$mapper->"url".
$html is the
"Pod::Tree::HTML" object itself.
$target is a
"Pod::Tree::Node" object representing
the the target of the link. See "target nodes" in
Pod::Tree::Node for information on interpreting
$target.
The "url" method must return
a string, which will be emitted as the value of the
"href" attribute of an HTML anchor:
"<a
href=""$url"">"..."</a>"
"Pod:Tree:HTML" provides the
"escape_2396" and
"assemble_url" methods for convenience
in implementing link mappers.
If the link mapper does not provide a
"url" method,
"Pod::Tree::HTML" will call
"map"
- ($base, $page,
$section) =
$mapper->"map"($base,
$page, $section,
$depth );
- Where
- $base
- is the URL given in the "base"
option.
- $page
- is the man page named in the L<> markup.
- $section
- is the man page section given in the L<> markup.
- $depth
- is the value of the "depth" option.
The "map" method may perform
arbitrary mappings on its arguments.
"Pod::Tree::HTML" takes the returned
values and constructs a URL of the form
[$base/][
$page".html"]["#"$fragment]
The "map" method is
- deprecated
- less flexible than the "url" method
- supported for backwards compatibility with older versions of
"Pod::Tree::HTML"
- "Pod::Tree::HTML::new: not enough arguments"
- (F) "new" called with fewer than 2
arguments.
- "Pod::Tree::HTML::new: Can't load POD from $source"
- (F) "new" couldn't resolve the
$source argument. See "Source resolution"
for details.
- "Pod::Tree::HTML::new: Can't write HTML to $dest"
- (F) "new" couldn't resolve the
$dest argument. See "Destination
resolution" for details.
- "Pod::Tree::HTML::new: Can't open $dest: $!"
- (F) The destination file couldn't be opened.
perl(1), "Pod::Tree",
"Pod::Tree::Node",
"Text::Template"
Steven McDougall, swmcd@world.std.com
Copyright (c) 1999-2009 by Steven McDougall. This module is free software; you
can redistribute it and/or modify it under the same terms as Perl itself.
Visit the GSP FreeBSD Man Page Interface. Output converted with ManDoc.
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