[PRL] use of variable-prefix ?

Mitchell Wand wand at ccs.neu.edu
Sat Jun 4 08:30:33 EDT 2011


I would like to distinguish constructors from variables, and constructor
applications from ordinary applications, using variable-prefix.
I'd like to write something like this:

(define-language sample
  [e
   x
   Kapp
   app]
  [app (x x)]
  [Kapp (K x)]
  [K (variable-prefix K)]
  [x variable-not-otherwise-mentioned])

But this doesn't work:  the symbol K1 matches both K and x, and (K1 x)
matches both app and Kapp.
Changing x to use variable-except doesn't do the job either, since
variable-except allows only a finite number of exceptions, not a pattern.

What am I missing?

--Mitch
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