Galculator

Blame information for rev 7

Line No.	Rev	Author	Line
1	1	paulosilva
2	7	paulosilva	{-# LANGUAGE FlexibleContexts, MultiParamTypeClasses, FlexibleInstances #-}
3	1	paulosilva	{-# OPTIONS_GHC -Wall #-}
4
5			-------------------------------------------------------------------------------
6
7			{- |
8			Module      :  Control.GalcError
9			Description :  Error messages of Galculator.
10			Copyright   :  (c) Paulo Silva
11			License     :  LGPL
12
13			Maintainer  :  paufil@di.uminho.pt
14			Stability   :  experimental
15			Portability :  portable
16
17			-}
18
19			-------------------------------------------------------------------------------
20
21			module Control.GalcError (
22			GalcError(..),
23			maybe2error,
24			list2error,
25			either2error,
26			) where
27
28	7	paulosilva	import Control.MonadOr
29	1	paulosilva	import Control.Monad.Error
30
31			-------------------------------------------------------------------------------
32
33			data GalcError =
34			UnknownError
35			| NoValueError
36			| ImpossibleError
37			| CustomError String
38			| ParsingError String
39			| UnificationError (String, String)
40			| CastingError (String, String)
41			| InferenceError GalcError String
42			| ReferenceError String
43			| MultiDefError String
44			| ModuleFileError String
45			| ModuleRefError String
46			| DerivationError
47			| ModeError
48			| NoProofError
49			| ExistingRefError String
50			| QedError String String
51			| NoOrderSetError
52	7	paulosilva	| RewriteError String
53			| EqualityError
54			| NestedError GalcError
55			| DecomposeError String String
56	1	paulosilva
57			-------------------------------------------------------------------------------
58
59			instance Show GalcError where
60			show = showGalcError
61
62			-------------------------------------------------------------------------------
63
64			instance Error GalcError where
65			noMsg = UnknownError
66			strMsg = CustomError
67
68			-------------------------------------------------------------------------------
69
70			instance MonadError GalcError [] where
71			throwError _ = []
72			catchError [] f = f NoValueError
73			catchError x@(_:_) _ = x
74
75			-------------------------------------------------------------------------------
76
77	7	paulosilva	instance MonadOr (Either GalcError) where
78			morelse (Left _) b = b
79			morelse a _ = a
80
81			-------------------------------------------------------------------------------
82
83	1	paulosilva	maybe2error :: MonadError GalcError m => GalcError -> Maybe a -> m a
84			maybe2error e Nothing  = throwError e
85			maybe2error _ (Just a) = return a
86
87			-------------------------------------------------------------------------------
88
89			list2error :: MonadError GalcError m => GalcError -> [a] -> m a
90			list2error e []    = throwError e
91			list2error _ (x:_) = return x
92
93			-------------------------------------------------------------------------------
94
95			either2error :: (Show e, MonadError GalcError m)
96			=> (e -> GalcError) -> Either e a -> m a
97			either2error f (Left e)  = throwError $ f e
98			either2error _ (Right v) = return v
99
100			-------------------------------------------------------------------------------
101
102			showGalcError :: GalcError -> String
103	7	paulosilva	showGalcError UnknownError =
104			"Unknown error!"
105			showGalcError NoValueError =
106			"No values found"
107			showGalcError ImpossibleError =
108			"The impossible has happened!"
109	1	paulosilva	showGalcError (CustomError err) = err
110	7	paulosilva	showGalcError (ParsingError err) =
111			"Parsing error:\n" ++ err
112	1	paulosilva	showGalcError (UnificationError (s1, s2)) =
113			"Unification error\nCannot unify " ++ s1 ++ " and " ++ s2
114			showGalcError (CastingError (s1, s2)) =
115			"Cannot cast " ++ s1 ++ " to " ++ s2
116			showGalcError (InferenceError err s) =
117	7	paulosilva	"Error in type inference:\n" ++ showGalcError err ++ "\n" ++ s
118	1	paulosilva	showGalcError (ReferenceError err) =
119			"Invalid reference: " ++ err
120			showGalcError (MultiDefError err) =
121			"Multiple definitions: " ++ err
122	7	paulosilva	showGalcError (ModuleFileError err) =
123			"Error opening file: " ++ err ++ ".gal"
124			showGalcError DerivationError =
125			"Inversion not expected"
126			showGalcError ModeError =
127			"Command not available in this mode"
128			showGalcError (ModuleRefError err) =
129			"Invalide module name: " ++ err
130			showGalcError NoProofError =
131			"Currently there is no proof"
132			showGalcError (ExistingRefError err) =
133			"Existing reference: " ++ err
134			showGalcError (QedError s1 s2) =
135			"Cannot equalize: " ++ s1 ++ " and " ++ s2
136			showGalcError (NoOrderSetError) =
137			"No order currently set"
138			showGalcError (RewriteError s) =
139			"Cannot rewrite: " ++ s
140			showGalcError EqualityError =
141			"Types are not equal"
142			showGalcError (NestedError e) =
143			showGalcError e
144			showGalcError (DecomposeError s1 s2) =
145			"Cannot match types: " ++ s1 ++ " and " ++ s2
146	1	paulosilva	-------------------------------------------------------------------------------
147