Sign.hs revision 8b054cade993ef373d564b2d74c9c5a2da48f8b7
{- |
Module : $Header$
Description : Definition of signatures for first-order logic with dependent types (DFOL)
-}
module DFOL.Sign where
import Common.Doc
import Common.DocUtils
-- signatures for DFOL - so far just the empty signature
data Sign = EmptySig deriving (Show, Eq, Ord)
-- the empty signature
emptySig :: Sign
emptySig = EmptySig
-- determines whether a signature is valid
isValidSig :: Sign -> Bool
isValidSig _ = True
-- pretty printing
instance Pretty Sign where
pretty = printSig
printSig :: Sign -> Doc
printSig EmptySig = text "Empty"