Here, for your interest, is a freshly-updated summary of the current state of
Haskell implementations, at least those known to us.
Simon Peyton Jones, Glasgow University.
Haskell: Current status
[Simon Peyton Jones wrote the original
Guy S., Phil W.,...
I ran into exactly this problem in two different applications.
The first was the same that Guy S. points out, namely adding
arbtrirary but well-typed annotations to a parse-tree. The solution I
eventually ended up using (after
Final Call for Papers
SIGPLAN Workshop on STATE in Programming Languages (SIPL)
June 12, 1993
Copenhagen, Denmark
Held in conjunction with FPCA and PEPM
This workshop will address the
Given your correction, I think that the type declaration
data FooTree a b = Leaf b | Node a (FooTree a b) a (FooTree a b)
will handle things only a little less neatly than the use of
wrappers, and will allow you to use type inference in much the
way you wish. What do you think? Cheers,
Date: Tue, 23 Feb 93 17:18:19 GMT
From: wadler [EMAIL PROTECTED]
...
I don't understand. Can't you handle this is as follows?
data FooTree a b = Leaf b | Node a (FooTree a b) a (FooTree a b)
data Annote a b c = MkAnnote Info (FooTree (Annote a b c) b) c
and
Date: Tue, 23 Feb 93 10:16:58 GMT
From: wadler [EMAIL PROTECTED]
Given your correction, I think that the type declaration
data FooTree a b = Leaf b | Node a (FooTree a b) a (FooTree a b)
will handle things only a little less neatly than the use of
wrappers, and will allow
Guy, You write,
But now suppose that some of the annotations refer to FooTree items
(another thing I forgot to say). I suppose I could do
data FooTree a b = Leaf b | Node a (FooTree a b)
a (FooTree a b)
