I'm not familiar with modal logic, but if modalities stack, you might be
able to do something like this.
-- Garrett Mitchener
{-# OPTIONS_GHC -fglasgow-exts #-}
module Test where
data L a
= F | T | Atom Int
| Neg (L a) | And (L a) (L a) | Or (L a) (L a)
| M (L a) -- the modali
Hi, list
I'm new to WinHugs, what's wrong with isUpper of my WinHugs?
Hugs> filter isUpper "ABCDEfgh"
ERROR - Undefined variable "isUpper"
Hugs> filter Char.isUpper "ABCDEfgh"
ERROR - Undefined qualified variable "Char.isUpper"
Hugs> :version
-- Hugs Version Sep 2006
Best Regards,
bingfeng
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