From: "M. Edward (Ed) Borasky" <znmeb@...>
Date: 2006-09-04T11:49:07+09:00
Subject: Re: Joel Spolsky on languages for web programming

Alex Young wrote:
> David Vallner wrote:
>> And another point is that quite a few Ruby frameworks do come to
>> defining a domain-specific language in Ruby - cf. Og data definition,
>> Puppet, rake. There's a (maybe not quite fine) line between a very
>> specific framework and a DSL that just gets crossed, and I don't
>> believe rubyists are the innocents to throw the first stone.
> That's not quite the same - those DSL's build upon a known and well
> understood foundation, because they use Ruby's syntax to their own ends.
> I'm inferring from the very little information that's out there that
> Wasabi has its own parser, and that makes it a very, very different
> beast to a DSL in the sense that I've come across the term in Ruby.

To use Martin Fowler's terminology, there are external DSLs -- a
language created for the domain and implemented with a parser, etc., in
some general-purpose language. And there are *internal* DSLs, written as
extensions/subsets inside a language like Ruby.

Rails and rake are internal DSLs, and Ruby makes internal DSL creation
much easier than many other languages. I can't tell from this thread
whether Wasabi is external or internal.

I hardly think of an external DSL as anything special any more. They've
been around as long as I've been programming, which is -- well, let's
just say your toaster has more compute power than the machine I learned
on. :) Almost every major decades-old Fortran code, for example, is
really implementing an external DSL.