[pro] Lisp and DSLs

[Didier Verna]

  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!

-- 
Resistance is futile. You will be jazzimilated.

Scientific site:   http://www.lrde.epita.fr/~didier
Music (Jazz) site: http://www.didierverna.com