summaryrefslogtreecommitdiff
path: root/prolog/lexer.py
blob: 32a25fc9cb91b6a2330efe63b12ce6e019d7e672 (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
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
#!/usr/bin/python3

# CodeQ: an online programming tutor.
# Copyright (C) 2015-2017 UL FRI
#
# This program is free software: you can redistribute it and/or modify it under
# the terms of the GNU Affero General Public License as published by the Free
# Software Foundation, either version 3 of the License, or (at your option) any
# later version.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
# details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.

import ply.lex as lex

operators = {
    r':-': 'FROM',
    r'-->': 'FROMDCG',
    r',': 'COMMA',
    r';': 'SEMI',
    r'->': 'IMPLIES',
    r'*->': 'SOFTCUT',
    r'\+': 'NOT',
    r'=': 'EQU',
    r'\=': 'NEQU',
    r'=@=': 'EQV',
    r'\=@=': 'NEQV',
    r'==': 'EQ',
    r'\==': 'NEQ',
    r'=..': 'UNIV',
    r'is': 'IS',
    r'=:=': 'EQA',
    r'=\=': 'NEQA',
    r'<': 'LT',
    r'=<': 'LE',
    r'>': 'GT',
    r'>=': 'GE',
    r'@<': 'LTL',
    r'@=<': 'LEL',
    r'@>': 'GTL',
    r'@>=': 'GEL',
    r'+': 'PLUS',
    r'-': 'MINUS',
    r'*': 'STAR',
    r'/': 'SLASH',
    r'//': 'SLASH2',
    r'<<': 'SHIFTLEFT',
    r'>>': 'SHIFTRIGHT',
    r'div': 'DIV',
    r'mod': 'MOD',
    r'rdiv': 'RDIV',
    r'rem': 'REM',
    r'xor': 'XOR',
    r'^': 'POW',
    r'**': 'POWSTAR',
    '/\\': 'AND',
    '\\': 'NEG',

    # CLP(FD)
    r'in': 'IN',
    r'ins': 'INS',
    r'..': 'THROUGH',
    r'#=': 'FDEQ',
    r'#\=': 'FDNEQ',
    r'#<': 'FDLT',
    r'#=<': 'FDLE',
    r'#>': 'FDGT',
    r'#>=': 'FDGE',
    r'\/': 'FDUNION',
}
tokens = sorted(list(operators.values())) + [
    'UINTEGER', 'UREAL',
    'NAME', 'VARIABLE', 'STRING',
    'LBRACKET', 'RBRACKET', 'LPAREN', 'RPAREN', 'PIPE', 'LBRACE', 'RBRACE',
    'PERIOD', 'INVALID'
]

# punctuation
t_LBRACKET = r'\['
t_RBRACKET = r'\]'
t_LPAREN = r'\('
t_RPAREN = r'\)'
t_PIPE = r'\|'
t_LBRACE = r'{'
t_RBRACE = r'}'

t_UINTEGER = r'[0-9]+'
t_UREAL    = r'[0-9]+\.[0-9]+([eE][-+]?[0-9]+)?|inf|nan'
t_VARIABLE = r'(_|[A-Z])[a-zA-Z0-9_]*'
t_STRING   = r'"(""|\\.|[^\"])*"'

# TODO support nested comments
def t_comment(t):
    r'(/\*(.|\n)*?\*/)|(%.*)'
    pass

def t_NAME(t):
    r"'(''|\\.|[^\\'])*'|[a-z][a-zA-Z0-9_]*|[-+*/\\^<>=~:.?@#$&]+|!|;|,"
    if t.value == '.':
        t.type = 'PERIOD'
    else:
        # return appropriate tokens for names that are operators
        t.type = operators.get(t.value, 'NAME')
    return t

t_ignore  = ' \t'

def t_newline(t):
    r'\n+'
    t.lexer.lineno += len(t.value)

def t_error(t):
    # TODO send this to stderr
    #print("Illegal character '" + t.value[0] + "'")
    t.type = 'INVALID'
    t.value = t.value[0]
    t.lexer.skip(1)
    return t

lexer = lex.lex(errorlog=lex.NullLogger())

if __name__ == '__main__':
    while True:
        try:
            s = input('> ')
        except EOFError:
            break
        if not s:
            continue

        lexer.input(s)
        tokens = list(lexer)
        print(tokens)