I'll try to respond more comprehensively about the more general question, but for this:
On Fri, Jun 10, 2011 at 2:12 PM, Richard Lawrence <richard.lawre...@berkeley.edu> wrote: > > And if it isn't possible, the cleanest workaround I can think of is to > tag all Variable values, like: > > (define-type Variable (Pair 'var Symbol)) > (define-predicate variable? Variable) Just use a struct: (struct: variable ([s : Symbol])) Now you have `variable' and `variable?' and `variable-s', and there's no confusion with pairs. That's how I'd write this code. -- sam th sa...@ccs.neu.edu _________________________________________________ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/users
