To further reduce the syntax burden, we can eliminate many calls to
the
text constructor by letting element constructors accept
an optional third argument for text content. In the common case, we
no longer have need to call
text. (Of course, should we want
to call
text for clarity, we still can.)
For example, the following fragment:
html {
head { title { text "Title" } };
body {
p { class_ "warning"; text "paragraph" }
}
};
can be simplified to this:
html {
head { title {} "Title" };
body {
p { class_ "warning" } "paragraph"
}
};
To effect the new syntax rules, we need only change the
_elem and define_vocabulary functions from our
original implementation. The changes are simple and marked with a
hash-bang (#!):
sub _elem {
my ($elem_name, $content_fn, $text) = @_; #! added $text arg
# an element is represented by the triple [name, attrs, children]
my $elem = [$elem_name, undef, undef];
do { local $__frag = $elem;
$content_fn->();
text($text) if defined $text; #! new line
};
push @{$__frag->[2]}, $elem;
}
sub define_vocabulary {
my ($elems, $attrs) = @_;
eval "sub $_(&@) { _elem('$_',\@_) }" for @$elems; #! proto
eval "sub ${_}_(\$) { _attr('$_',\@_) }" for @$attrs;
}
Can you spot any other syntax-reduction opportunities?
Cheers,
Tom
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