[Haskell-cafe] The rmonad package is mysterious

Simon Marechal simon at banquise.net
Wed Apr 10 20:30:55 CEST 2013


I tried to do something simple using the rmonad package (attached).

I followed the example that's in haddocks (it is wrong, constraints has
no arguments), grabbed the list of extensions from rmonad's source, but
this program doesn't typecheck:

Could not deduce (Hashable a) arising from a use of `HM.singleton'

This seems to be an obvious use of this package ... am I missing something ?
-------------- next part --------------
A non-text attachment was scrubbed...
Name: test.hs
Type: text/x-haskell
Size: 635 bytes
Desc: not available
URL: <http://www.haskell.org/pipermail/haskell-cafe/attachments/20130410/dd3dbc28/attachment.hs>


More information about the Haskell-Cafe mailing list