Hello,
The new hugs is looking very nice thank you.
I have a problem with some things surrounding ST though.
o) the demo Ldfs.hs does not work.
It uses thenST and returnST which are not exported by
the ST library.
o) :t runST results in
ERROR: Syntax error in expression (unexpected end of input)
Is this the expected behaviour?
o) Replacing thenST with >>= and returnST with return and retrying
the Ldfs.hs, I get
ERROR "Ldfs.hs" (line 90): Type error in encapsulation
*** expression : runST (mkEmpty bnds >>= (\m -> chop m ts))
*** term : mkEmpty bnds >>= (\m -> chop m ts)
*** type : ST a [Tree Vertex]
*** does not match : ST b [Tree Vertex]
which is similar to the error that I get from HBC:
Errors:
"Ldfs.hs", line 104, [65] Cannot unify types:
RunST a
and ST b (Forest Vertex)
in runST ((>>=) (mkEmpty A1_prune) (\m -> chop m A2_prune))
in prune
when I compileit, but unfortunately not from GHC (which compiles is
successfully). Can anybody explain the different behaviour?
Thanks
Jon
PS. Who is not on the hugs bugs list
