From: Siemen Baader <siemenbaader@...>
Date: 2009-11-17T00:40:45+09:00
Subject: Re: Traversing the contents of a proc (for a DSL)

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On Mon, Nov 16, 2009 at 1:51 PM, Brian Candler <b.candler@pobox.com> wrote:

> Siemen Baader wrote:
> > I'm playing with a small DSL for HTML, which should look like this.
> >
> > html {
> >   head { title {"Hello World"} }
> >   body {
> >     h1 { "hello"}
> >     p {
> >      "text body"
> >      "more text"
> >     }
> >   }
> > }
> >
> > If it is possible to recursively traverse through the statements in
> > each block, I could join the lines together with the + operator, and
> > the implementation would be fairly easy - just recursive calls that
> > return text. But it does not look like this is possible...
>
> Two string literals on the same line are concatenated - so in the above
> example you could get away with a simple pre-processor that joins the
> lines together in the right places.
>
> >> "foo" "bar"
> => "foobar"
> >>
>
> However this won't work for
>
>   str1
>   str2
>
> If this is what you want - i.e. each expression appearing on a line of
> its own has its value sent to the output string - then probably native
> Ruby is not the right tool. HAML, ERB and Cucumber are examples of DSLs
> where a non-Ruby syntax fits better.
>

Yes. Again, this is more an exercise to see what can be done with an inline
DSL, so I'll just stick with what I got.

It would have been quite easy with Lisp though, as I would have access to
each line and join them .. But apart from that, I'm not fluent with Lisp :)


> --
> Posted via http://www.ruby-forum.com/.
>
>

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