See for example:

Easy yUML Dialect: UML Diagram Scripting Tool for Mere Mortals – Part I (Use Case Diagram)
http://reboltutorial.com/blog/easy-yuml-dialect-for-mere-mortals/

You can even try it online:
http://reboltutorial.com/blog/try-the-easy-yuml-domain-specific-language-online-without-downloading-rebol/

The hard stuff is the language design and its affordances (including error recovery). In other words, deciding how to engage the target audience and what to build…

I don’t think M intends to really help with the problem of (domain-specific) language design. As you said, it seems better suited for data transformation tasks. I’ve seen plenty of cases where programmers used overcomplicated and slow “regular expressions” to extract and transform structured data for lack of a neat way to express a grammar.

That said, I’m getting a little tired of markup, notations, schema definitions, and grammars for data. What about semantics? What about behavior?

Thanks for taking the time to weigh in.

In looking at both your post and Frans’, I think we’re not being super-clear on our side when we talk about M and textual DSLs.

While it is possible to write the grammar for a “capital-L” language in M, that’s not where most of us on the team see the primary use case of M.

Rather, the sweet spot (in my mind at least) is in enabling tailored syntax over schematized data – that is, the schema dominates the design, not the language per se.

In M, you can define a schema and get a “default” syntax for values, but, as with XML, JSON and S-exprs, that syntax lacks visual cues from the domain. For people that want a more tailored syntax, M allows them to write a grammar to “transform the data” from linear Unicode to structured data.

Independent of the design center, you raise a valid question as to whether developers can write grammars.

I love that question and my team is working hard to make the answer “yes” for as large a body of developers as possible. We have a lot of work to do, but I’m pretty hopeful we can advance the state-of-the-practice enough to make the effort worthwhile.

Thanks again for taking the time to weigh in.

DB