HTML::AsSubs - functions that construct a HTML syntax tree


HTML-Tree documentation Contained in the HTML-Tree distribution.

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NAME

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HTML::AsSubs - functions that construct a HTML syntax tree

SYNOPSIS

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 use HTML::AsSubs;
 $h = body(
	   h1("This is the heading"),
	   p("This is the first paragraph which contains a ",
	     a({href=>'link.html'}, "link"),
	     " and an ",
	     img({src=>'img.gif', alt=>'image'}),
	     "."
	    ),
	  );
 print $h->as_HTML;

DESCRIPTION

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This module exports functions that can be used to construct various HTML elements. The functions are named after the tags of the corresponding HTML element and are all written in lower case. If the first argument is a hash reference then it will be used to initialize the attributes of this element. The remaining arguments are regarded as content.

For a similar idea (i.e., it's another case where the syntax tree of the Perl source mirrors the syntax tree of the HTML produced), see HTML::Element's new_from_lol method.

For what I now think is a cleaner implementation of this same idea, see the excellent module XML::Generator, which is what I suggest for actual real-life use. (I suggest this over HTML::AsSubs and over CGI.pm's HTML-making functions.)

ACKNOWLEDGEMENT

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This module was inspired by the following message:

 Date: Tue, 4 Oct 1994 16:11:30 +0100
 Subject: Wow! I have a large lightbulb above my head!

 Take a moment to consider these lines:

 %OVERLOAD=( '""' => sub { join("", @{$_[0]}) } );

 sub html { my($type)=shift; bless ["<$type>", @_, "</$type>"]; }

 :-)  I *love* Perl 5!  Thankyou Larry and Ilya.

 Regards,
 Tim Bunce.

 p.s. If you didn't get it, think about recursive data types: html(html())
 p.p.s. I'll turn this into a much more practical example in a day or two.
 p.p.p.s. It's a pity that overloads are not inherited. Is this a bug?

BUGS

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The exported link() function overrides the builtin link() function. The exported tr() function must be called using &tr(...) syntax because it clashes with the builtin tr/../../ operator.

SEE ALSO

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HTML::Element, XML::Generator

Private Functions

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_elem()

The _elem() function is wrapped by all the html 'tag' functions. It takes a tag-name, optional hashref of attributes and a list of content as parameters.


HTML-Tree documentation Contained in the HTML-Tree distribution.
package HTML::AsSubs;

use warnings;
use strict;
use vars qw(@ISA $VERSION @EXPORT);

require HTML::Element;
require Exporter;
@ISA = qw(Exporter);

$VERSION = 4.2;

# Problem: exports so damned much.  Has no concept of "export only HTML4
#  elements".  TODO:?? make something that make functions that just
#  wrap XML::Generator calls?

use vars qw(@TAGS);
@TAGS = qw(html
    head title base link meta isindex nextid script style
    body h1 h2 h3 h4 h5 h6 p pre div blockquote
    a img br hr
    ol ul dir menu li
    dl dt dd
    dfn cite code em kbd samp strong var address span
    b i u tt
    center font big small strike
    sub sup
    table tr td th caption
    form input select option textarea
    object applet param
    map area
    frame frameset noframe
);

for (@TAGS) {
    my $code;
    $code = "sub $_ { _elem('$_', \@_); }\n";
    push( @EXPORT, $_ );
## no critic
    eval $code;
## use critic
    if ($@) {
        die $@;
    }
}

sub _elem {
    my $tag = shift;
    my $attributes;
    if ( @_ and defined $_[0] and ref( $_[0] ) eq "HASH" ) {
        $attributes = shift;
    }
    my $elem = HTML::Element->new( $tag, %$attributes );
    $elem->push_content(@_);
    $elem;
}

1;