Dear friends,
I'm starting to write a chapter for an upcoming book on domain specific languages. The chapter is called (tentatively):
Extensible languages -- blurring the distinction between DSLs and GPLs
GPL meaning General Purpose Language in this context ;-)
My intention is to demonstrate how the task of implementing a DSL is made easier when it boils down to an extension or subset of your original GPL (hence reusing its infrastructure), instead of being a totally different language, only written on top of the other.
Obviously, I'm going to illustrate this with Common Lisp, and I intend to speak of dynamicity (not only dynamic typing, but in general all things that can be deferred to the run-time), introspection, intersession, structural or procedural reflexivity, meta-object protocols (not sure about this one), macro systems and JIT-compilation. Also, more specifically to Lisp, reader macros (compiler macros maybe?), the condition system (and its ability to *not* unwind) and restarts.
Right now, I would like to know if any of you have DSL "pearls", nice examples of DSLs that you have written in Lisp by using some of its features in a clever or elegant way. I would also gladly accept any point of view or comment on what's important to mention, in terms of design principle or anything else, things that I may have missed in the list above.
Thank you very much in advance!