in reply to Embedding a mini-language for XML construction into Perl
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:
can be simplified to this:html { head { title { text "Title" } }; body { p { class_ "warning"; text "paragraph" } } };
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
Tom Moertel : Blog / Talks / CPAN / LectroTest / PXSL / Coffee / Movie Rating Decoder
|
---|
Replies are listed 'Best First'. | |
---|---|
Re: Simplifying the syntax further
by Aristotle (Chancellor) on Nov 22, 2005 at 11:32 UTC | |
by tmoertel (Chaplain) on Nov 22, 2005 at 15:59 UTC | |
by TimToady (Parson) on Nov 22, 2005 at 16:52 UTC | |
by Aristotle (Chancellor) on Nov 22, 2005 at 16:48 UTC |
In Section
Meditations