Textual Domain-Specific language (DSL) development with Microsoft Visual Studio

Question

I did some searches on developing a DSL in visual studio. At the beginning, I found out there is a Visualization and Modeling SDK for VS2010. It has a tool called DSL tool. But it seems that it is only for graphical DSL development.

Then I saw some posts saying "Oslo" is a tool for developing textual DSL, which "was" a Microsoft product - Microsoft no longer supports the tool. http://blogs.msdn.com/b/modelcitizen/archive/2010/09/22/update-on-sql-server-modeling-ctp-repository-modeling-services-quot-quadrant-quot-and-quot-m-quot.aspx

Therefore, I would like to know if I want to develop a textual DSL, what tool is the best? What do you think if I implement a DSL parser making use of F# powerpack with FSLex and FSYacc?

Answer 1

I am currently developing several external text-based DSLs using FsLex/FsYacc. I was using a hand parser, but I find the FsLex/FsYacc much easier to maintain in the design stage.

FsLex/FsYacc are not as sophisticated as ANTLR, but since most DSLs are fairly simple, FsLex/FsYacc are a perfectly sound choice for use within Visual Studio. And keeping DSLs simple is a good thing, since they are intended to be restricted and simple to learn.

I find Martin Fowler's book to be a good resource, less for the examples and details than as an encyclopedia of DSL ideas. His discussion of useability and other design aspects of DSLs is also worth reading. As Toumas indicated, it does not cover either F# or functional languages. Mr. Fowler writes that he lacked the experience in those subjects to bring the book to market in a timely way.

Having praised FsLex/FsYacc, I do still wish someone would write a good ANTLR back-end for F#. :)

-Neil

Answer 2

I am a fan of embedded DSLs, a la

http://lorgonblog.wordpress.com/2010/04/15/using-vs2010-to-edit-f-source-code-and-a-little-logo-edsl/

http://lorgonblog.wordpress.com/2010/04/16/fun-with-turtle-graphics-in-f/

where you just use leverage F# syntax with some good function names and possibly other syntax cleverness (lists, workflows, ...) to get code that "looks like maybe it is another language" but is actually just F#.

But yes, for external DSLs, you just need a grammar/parser/etc tool chain, and either FsLex/FsYacc, or maybe ANTLR or FParsec are various choices. (I don't have enough experience with any of these to know trade-offs among them.)