From: Robert Klemme <bob.news@...>
Date: 2005-04-11T16:49:37+09:00
Subject: Re: groovy-like xml selection


"Luke Graham" <spoooq@gmail.com> schrieb im Newsbeitrag
news:c6afaed005041020493e803be4@mail.gmail.com...
> Hi list,
>
> Ive taken a quick look at groovy for the first time, and saw an
> interesting idea. Using xml to build an object tree, its possible to
> write code like this...
>
> <foo>
>   <bar>
>     <jim age="1"/>
>     <joe age="2"/>
>   </bar>
>   <bar/>
> </foo>
>
> foo.bar.star.select { |it| it[@age] == "1" && it.parent.name == "bar"
> && it.star.count == 0 }
>
> Note that foo.bar and foo.bar.star are not arrays, rather
> transparently hide multiple elements in one object. Requesting a value
> would be handled by the first element.
>
> The interesting part is that theres no quotes around the path
> expression, its just evaluated in the context of bar. Complex
> expressions could be broken into multiple selects and combined with
> normal array operations.
>
> Im sure someones done the xml->object (method in this case) thing, but
> has the native path trick been tried in ruby yet?

REXML comes pretty close.  I'm sure with a small addition like this one
you get pretty far:

class REXML::Element
  def method_missing(sym,*a,&b)
    elements[sym.to_s] or super
  end
end

Maybe you should add this to module REXML::Node.

> PS. Extra kudos if someone implements not only the above, but foo.bar
> { ... }, where foo and bar are methods...

Dunno what you mean here.  foo and bar have to be methods.

Regards

    robert