{- |

Module : $Header$

Description : data types for consistency aka conservativity

Copyright : (c) Christian Maeder, DFKI GmbH 2008

License : similar to LGPL, see HetCATS/LICENSE.txt or LIZENZ.txt

Maintainer : Christian.Maeder@dfki.de

Stability : provisional

Portability : portable

Data types for conservativity

-}

module Common.Consistency where

import Data.Char (toLower)

import Common.Doc

import Common.DocUtils

import Common.AS_Annotation

import Common.Result

{- | Conservativity annotations. For compactness, only the greatest applicable

value is used in a DG. PCons stands for prooftheoretic conservativity as

required for extending imports (no confusion) in Maude -}

data Conservativity =

Inconsistent

| Unknown String

| None

| PCons

| Cons

| Mono

| Def

deriving (Show, Eq, Ord)

showConsistency :: Conservativity -> String

showConsistency c = case c of

Cons -> "Consistent"

Unknown str -> "unkown if being consistent. Cause is : " ++ str

_ -> show c

showConsistencyStatus :: Conservativity -> String

showConsistencyStatus cs = case cs of

Inconsistent -> "not conservative"

Unknown str -> "unkown if being conservative. Cause is : " ++ str

_ -> map toLower $ show cs

instance Pretty Conservativity where

pretty = text . showConsistencyStatus

data ConservativityChecker sign sentence morphism = ConservativityChecker

{ checkerId :: String

, checkConservativity

:: (sign, [Named sentence])

-> morphism

-> [Named sentence]

-> IO (Result (Maybe (Conservativity, [sentence]))) }