From: Philipp Meier <meier@...>
Date: 2002-11-09T21:12:57+09:00
Subject: Re: An alternative HTML generation syntax

Am Sam, 2002-11-09 um 09.47 schrieb Philip Mak:

> It would be this:
> 
> HTML.new { p {
>     t 'NEW!' if flag == 'new'
>     t 'UPDATED!' if flag == 'updated'
>     br
>     if numparts > 1
>         t 'Parts:'
>         (1..numparts).each do |i|
>             a(:href => "#{i}.asp") { "[#{i}]" }
>         end
>     end
> } }
> 
> The HTML class would be something like this:
> 
> class HTML
>     def initialize(&block)
>         @buff = ''
>         self.instance_eval &block

Why not yield?

>         puts @buff
>     end
> 
>     def p
>         @buff += "<P>#{yield || @buff}</P>"
>     end
>     # define a, h1, h2, etc. and all the other HTML tags similarly
> end

This should certainly work. I'd suggest using method_missing and have a
class local configuration which says elements html allows and which
attributes are needed. Sth. like i micro dtd:

class HTML
	@@dtd = { :html => {},
                  :head => {},
                  :title => {},
                  :body => {:bgcolor, :link, :vlink, :alink}
                }
...
  def methods_missing(symbol, *attrs) 
    raise "Invalid element: #{symbol}" unless @@dtd.has_key? symbol
    @buff << "<#{symbol}>#{yield || @buff}</#{symbol}>"
  end
end

You can go even further and use a DTD parser to decouple this nifty tool
from HTML. Make it a Provider of a SAX Stream, e.g.

-billy.
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