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
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
|
module Parsers where
import Operations
import Char
infixr 2 |||, +||
infixr 3 ***
infixr 5 .>.
infixr 5 ...
infixr 5 ....
infixr 5 +..
infixr 5 ..+
infixr 6 |>
infixr 3 <<<
-- some parser combinators a` la Wadler and Hutton
-- no longer used in many places in GF
type Parser a b = [a] -> [(b,[a])]
parseResults :: Parser a b -> [a] -> [b]
parseResults p s = [x | (x,r) <- p s, null r]
parseResultErr :: Parser a b -> [a] -> Err b
parseResultErr p s = case parseResults p s of
[x] -> return x
[] -> Bad "no parse"
_ -> Bad "ambiguous"
(...) :: Parser a b -> Parser a c -> Parser a (b,c)
(p ... q) s = [((x,y),r) | (x,t) <- p s, (y,r) <- q t]
(.>.) :: Parser a b -> (b -> Parser a c) -> Parser a c
(p .>. f) s = [(c,r) | (x,t) <- p s, (c,r) <- f x t]
(|||) :: Parser a b -> Parser a b -> Parser a b
(p ||| q) s = p s ++ q s
(+||) :: Parser a b -> Parser a b -> Parser a b
p1 +|| p2 = take 1 . (p1 ||| p2)
literal :: (Eq a) => a -> Parser a a
literal x (c:cs) = [(x,cs) | x == c]
literal _ _ = []
(***) :: Parser a b -> (b -> c) -> Parser a c
(p *** f) s = [(f x,r) | (x,r) <- p s]
succeed :: b -> Parser a b
succeed v s = [(v,s)]
fails :: Parser a b
fails s = []
(+..) :: Parser a b -> Parser a c -> Parser a c
p1 +.. p2 = p1 ... p2 *** snd
(..+) :: Parser a b -> Parser a c -> Parser a b
p1 ..+ p2 = p1 ... p2 *** fst
(<<<) :: Parser a b -> c -> Parser a c -- return
p <<< v = p *** (\x -> v)
(|>) :: Parser a b -> (b -> Bool) -> Parser a b
p |> b = p .>. (\x -> if b x then succeed x else fails)
many :: Parser a b -> Parser a [b]
many p = (p ... many p *** uncurry (:)) +|| succeed []
some :: Parser a b -> Parser a [b]
some p = (p ... many p) *** uncurry (:)
longestOfMany :: Parser a b -> Parser a [b]
longestOfMany p = p .>. (\x -> longestOfMany p *** (x:)) +|| succeed []
closure :: (b -> Parser a b) -> (b -> Parser a b)
closure p v = p v .>. closure p ||| succeed v
pJunk :: Parser Char String
pJunk = longestOfMany (satisfy (\x -> elem x "\n\t "))
pJ :: Parser Char a -> Parser Char a
pJ p = pJunk +.. p ..+ pJunk
pTList :: String -> Parser Char a -> Parser Char [a]
pTList t p = p .... many (jL t +.. p) *** (\ (x,y) -> x:y) -- mod. AR 5/1/1999
pTJList :: String -> String -> Parser Char a -> Parser Char [a]
pTJList t1 t2 p = p .... many (literals t1 +.. jL t2 +.. p) *** (uncurry (:))
pElem :: [String] -> Parser Char String
pElem l = foldr (+||) fails (map literals l)
(....) :: Parser Char b -> Parser Char c -> Parser Char (b,c)
p1 .... p2 = p1 ... pJunk +.. p2
item :: Parser a a
item (c:cs) = [(c,cs)]
item [] = []
satisfy :: (a -> Bool) -> Parser a a
satisfy b = item |> b
literals :: (Eq a,Show a) => [a] -> Parser a [a]
literals l = case l of
[] -> succeed []
a:l -> literal a ... literals l *** (\ (x,y) -> x:y)
lits :: (Eq a,Show a) => [a] -> Parser a [a]
lits ts = literals ts
jL :: String -> Parser Char String
jL = pJ . lits
pParenth p = literal '(' +.. pJunk +.. p ..+ pJunk ..+ literal ')'
pCommaList p = pTList "," (pJ p) -- p,...,p
pOptCommaList p = pCommaList p ||| succeed [] -- the same or nothing
pArgList p = pParenth (pCommaList p) ||| succeed [] -- (p,...,p), poss. empty
pArgList2 p = pParenth (p ... jL "," +.. pCommaList p) *** uncurry (:) -- min.2 args
longestOfSome p = (p ... longestOfMany p) *** (\ (x,y) -> x:y)
pIdent = pLetter ... longestOfMany pAlphaPlusChar *** uncurry (:)
where alphaPlusChar c = isAlphaNum c || c=='_' || c=='\''
pLetter = satisfy (`elem` (['A'..'Z'] ++ ['a'..'z'] ++
['À' .. 'Û'] ++ ['à' .. 'û'])) -- no such in Char
pDigit = satisfy isDigit
pLetters = longestOfSome pLetter
pAlphanum = pDigit ||| pLetter
pAlphaPlusChar = pAlphanum ||| satisfy (`elem` "_'")
pQuotedString = literal '"' +.. pEndQuoted where
pEndQuoted =
literal '"' *** (const [])
+|| (literal '\\' +.. item .>. \ c -> pEndQuoted *** (c:))
+|| item .>. \ c -> pEndQuoted *** (c:)
pIntc :: Parser Char Int
pIntc = some (satisfy numb) *** read
where numb x = elem x ['0'..'9']
|
