Writing for both State and StateT
Mark Carroll
mark@chaos.x-philes.com
Tue, 22 Apr 2003 15:59:13 -0400 (EDT)
On Tue, 22 Apr 2003, Jon Cast wrote:
> When you have two identical methods like this, you can try removing the
> type from one and seeing what hugs or ghci thinks the type is. Then,
> you can specialize that if you want.
Unfortunately, in this case, with that function in isolation I get,
Ambiguous type variable(s) `s', `m'
in the constraint `MonadState s m'
arising from use of `get' ....
and with it being used in other functions I get things like,
Inferred type is less polymorphic than expected
Quantified type variable `m' escapes
or similar. That is, I haven't yet managed to make the function compile
without a type signature!
I have found your technique useful in other contexts, though. (-:
-- Mark