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
|
{
-- Tests the basic operation.
module Main where
import Data.Char (toUpper)
import Control.Monad
import System.Exit
import System.IO
}
%wrapper "monad"
@word = [A-Za-z]+
tokens :-
<0> {
"αω" { string }
[AΓ] { character }
. { other }
}
{
string :: AlexInput -> Int -> Alex String
string (_,_,_,_) _ = return "string!"
other :: AlexInput -> Int -> Alex String
other (_,_,_,input) len = return (take len input)
character :: AlexInput -> Int -> Alex String
character (_,_,_,_) _ = return "PING!"
alexEOF :: Alex String
alexEOF = return "stopped."
scanner :: String -> Either String [String]
scanner str = runAlex str $ do
let loop = do tok <- alexMonadScan
if tok == "stopped." || tok == "error."
then return [tok]
else do toks <- loop
return (tok:toks)
loop
main :: IO ()
main = do
let test1 = scanner str1
when (test1 /= out1) $
do hPutStrLn stderr "Test 1 failed:"
print test1
exitFailure
let test2 = scanner str2
when (test2 /= out2) $
do hPutStrLn stderr "Test 2 failed:"
print test2
exitFailure
let test3 = scanner str3
when (test3 /= out3) $
do hPutStrLn stderr "Test 3 failed:"
print test3
exitFailure
let test4 = scanner str4
when (test4 /= out4) $
do hPutStrLn stderr "Test 4 failed:"
print test4
exitFailure
str1 = "A."
out1 = Right ["PING!",".","stopped."]
str2 = "\n"
out2 = Left "lexical error at line 1, column 1"
str3 = "αω --"
out3 = Right ["string!"," ","-","-","stopped."]
str4 = "βΓ"
out4 = Right ["β","PING!","stopped."]
}
|
