[Haskell-cafe] traversing a tree using monad.cont

[Anatoly Yakovenko]

its a syntax tree, and at some point i hit a type reference who'se
declaration will be satisfied in some other part of the tree.  the
type references are always leaves, so when i hit a typeref, i just
want to continue along the rest of the parser until i hit a
declaration.  My current solution is to do multiple passes, store the
declarations in a map in one pass then resolve all the type references
in another, but that's kind of boring.