blob: dd40e23a2d83a6661db6656b8ec16b3c21da2b13 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
|
module Parser (
ThueProgram(..),
Rule(..),
State,
parseThue
) where
import Text.ParserCombinators.Parsec
data ThueProgram = ThueProgram { thueRules :: [Rule]
, thueInitialState :: State }
deriving (Show)
data Rule = Rule { original :: State
, replacement :: State }
deriving (Show)
type State = String
parseThue :: String -> Either ParseError ThueProgram
parseThue = parse thue "error"
thue = do
rs <- many rule
separatorLine
i <- initialState
eof
return (ThueProgram rs i)
rule = do
o <- ruleState
separator
r <- state
eol
return (Rule o r)
separatorLine = whiteSpace >> separator >> whiteSpace >> eol
separator = string "::="
initialState = do
s <- state `sepEndBy` eol
return (concat s)
ruleState = many ruleStateChar
ruleStateChar = noneOf "\n\r:"
<|> try (do { char ':'; notFollowedBy (string ":="); return ':'})
state = many stateChar
stateChar = noneOf "\n\r"
whiteSpace = many (oneOf "\t ")
eol = try (string "\r\n")
<|> try (string "\n\r")
<|> try (string "\r")
<|> try (string "\n")
|
