subtermN?

[ocharles]

Is it possible to have a subterm generator that gives a list of subterms of arbitrary length? A use case might be:

data Expr = 
  ...
  | List [Expr]

That is, a language which has list expressions of arbitrary length.

Given Range, maybe this is something like subtermNM :: MonadGen m => Range -> m a -> ([a] -> m a)?