From: Brian Candler <b.candler@...>
Date: 2009-11-16T21:51:59+09:00
Subject: Re: Traversing the contents of a proc (for a DSL)

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.
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