-
Notifications
You must be signed in to change notification settings - Fork 0
/
tokens.py
148 lines (130 loc) · 4.18 KB
/
tokens.py
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
144
145
146
147
148
import enum
tokens = []
class Token:
def __init__(self, kind, content=''):
self.kind = kind
self.content = content
def __repr__(self):
return f'Token: {self.kind}'
def __eq__(self, t):
return self.kind == t
class TokenKind(enum.Enum):
END = '$'
EMPTY = 'empty'
IDENTIFIER = 'identifier'
NUMCONST = 'numconst'
KEYWORD = 'keyword'
SYMBOL = 'symbol'
# Keywords
VOID = 'void'
INT = 'int'
BOOL = 'bool'
RETURN = 'return'
IF = 'if'
ELSE = 'else'
COLON = ':'
SEMICOLON = ';'
L_SQR_BRCKT = '['
R_SQR_BRCKT = ']'
L_CRL_BRCKT = '{'
R_CRL_BRCKT = '}'
L_PAREN = '('
R_PAREN = ')'
COMMA = ','
EQUAL_TO = '='
PLUS = '+'
MINUS = '-'
MUL = '*'
DIV = '/'
BT = '>'
BE = '>='
LT = '<'
LE = '<='
NE = '!='
EQ = '=='
def create_tokens(file_name):
with open(file_name, 'r') as f:
line = f.readline()
while line != '':
lexify_string(line)
line = f.readline()
tokens.append(Token(TokenKind.END))
def lexify_string(line):
if line[len(line) - 1] != '\n':
line = line + '\n'
curr_p, start_p = 0, 0
s = line[curr_p]
while (s != '\n'):
token = None
if (s == ','): token = Token(TokenKind.COMMA)
elif (s == ':'): token = Token(TokenKind.COLON)
elif (s == ';'): token = Token(TokenKind.SEMICOLON)
elif (s == '['): token = Token(TokenKind.L_SQR_BRCKT)
elif (s == ']'): token = Token(TokenKind.R_SQR_BRCKT)
elif (s == '{'): token = Token(TokenKind.L_CRL_BRCKT)
elif (s == '}'): token = Token(TokenKind.R_CRL_BRCKT)
elif (s == '('): token = Token(TokenKind.L_PAREN)
elif (s == ')'): token = Token(TokenKind.R_PAREN)
elif (s == '+'): token = Token(TokenKind.PLUS)
elif (s == '-'): token = Token(TokenKind.MINUS)
elif (s == '*'): token = Token(TokenKind.MUL)
elif (s == '/'): token = Token(TokenKind.DIV)
elif (s == '!'):
if line[curr_p + 1] == '=':
curr_p += 1
token = Token(TokenKind.NE)
else:
raise Exception(f'unknown symbol for not equal operator: {line[curr_p + 1]}')
elif (s == '>'):
if line[curr_p + 1] == '=':
curr_p += 1
token = Token(TokenKind.BE)
else:
token = Token(TokenKind.BT)
elif (s == '<'):
if line[curr_p + 1] == '=':
curr_p += 1
token = Token(TokenKind.LE)
else:
token = Token(TokenKind.LT)
elif (s == '='):
if line[curr_p + 1] == '=':
curr_p += 1
token = Token(TokenKind.EQ)
else:
token = Token(TokenKind.EQUAL_TO)
# Identifier
elif ((s >= 'a' and s <= 'z') or (s >= 'A' and s <= 'Z') or (s == '_')):
curr_p += 1
s = line[curr_p]
while ((s >= 'a' and s <= 'z') or (s >= 'A' and s <= 'Z') or (s == '_') or (s >= '1' and s <= '9') and curr_p < len(line) - 1):
curr_p += 1
s = line[curr_p]
curr_p -= 1
lex = line[start_p: curr_p + 1]
try:
t_kind = TokenKind(lex)
token = Token(t_kind)
except ValueError:
token = Token(TokenKind.IDENTIFIER, lex)
# Numbers
elif (s >= '1' and s <= '9'):
while (s >= '1' and s <= '9' and curr_p < len(line) - 1):
curr_p += 1
s = line[curr_p]
curr_p -= 1
token = Token(TokenKind.NUMCONST, int(line[start_p: curr_p + 1]))
curr_p += 1
start_p = curr_p
s = line[curr_p]
if token:
tokens.append(token)
def token_is(index, kind):
return len(tokens) > index and tokens[index].kind == kind
def token_in(index, kinds):
return len(tokens) > index and tokens[index].kind in kinds
def match_token(index, kind):
if token_is(index, kind):
return index + 1
else:
raise Exception(f'Error matching token: {kind}, current token: {tokens[index]}')