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
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
|
from consts import *
from tokenizer import Token
class ParserError(Exception):
pass
class Node:
def __init__(self, node_type, *, value=None, subtype=None):
self.type = node_type
self.value = value
self.subtype = subtype
self.parent = None
self.right = None
self.left = None
def __eq__(self, other):
return self.type == other.type and self.value == other.value
def __repr__(self):
# NUMBER, OPERATOR, SYMBOL, FUNCALL, UNARY, ASSIGNMENT, *_
if self.type == NodeType.NUMBER:
return f"Node({self.value})"
if self.type == NodeType.OPERATOR:
return f"Node({self.subtype})"
if self.type == NodeType.SYMBOL:
return f"Node(SYMBOL {self.value})"
if self.type == NodeType.FUNCALL:
return f"Node(FUNCALL {self.value})"
if self.type == NodeType.UNARY:
return f"Node(UNARY {self.subtype})"
if self.type == NodeType.ASSIGNMENT:
return f"Node(ASSIGNMENT)"
return "Node(repr not defined)"
__str__ = __repr__
def parse_parenthesis(tokens, start):
end = start
depth = 0
while True:
token = tokens[end]
if token.type == TokenType.RIGHT_PARENTHESIS:
depth -= 1
if token.type == TokenType.LEFT_PARENTHESIS:
depth += 1
if depth == 0 and token.type == TokenType.RIGHT_PARENTHESIS:
break
end += 1
node, _ = parse_expr(tokens[start + 1: end], 0)
return node, end
def parse_args(tokens, start):
end = start
depth = 0
while True:
token = tokens[end]
if token.type == TokenType.RIGHT_PARENTHESIS:
depth -= 1
if token.type == TokenType.LEFT_PARENTHESIS:
depth += 1
if depth == 0 and token.type == TokenType.RIGHT_PARENTHESIS:
break
end += 1
args = []
arg = []
for token in tokens[start + 1: end]:
if token.type != TokenType.COMMA:
arg.append(token)
else:
args.append(arg.copy())
arg.clear()
if len(arg) != 0:
args.append(arg)
tmp = []
for arg in args:
node, _ = parse_expr(arg, 0)
tmp.append(node)
return tmp
def parse_expr(tokens, start):
state = State.NAME
i = start
current_node = None
while i < len(tokens):
token = tokens[i]
if state == State.OPERATOR and token.type == TokenType.LEFT_PARENTHESIS:
args = parse_args(tokens, i)
current_node.type = NodeType.FUNCALL
current_node.left = Node(NodeType.SYMBOL, value=current_node.value)
current_node.right = Node(NodeType.ARGUMENTS, value=args)
elif token.type in [TokenType.LEFT_PARENTHESIS, TokenType.NUMBER, TokenType.SYMBOL] or token.subtype == TokenType.UNARY:
if token.type == TokenType.LEFT_PARENTHESIS:
node, i = parse_parenthesis(tokens, i)
state = State.NAME
elif token.type == TokenType.NUMBER:
node = Node(NodeType.NUMBER, value=token.value)
state = State.OPERATOR
elif token.type == TokenType.SYMBOL:
node = Node(NodeType.SYMBOL, value=token.value)
state = State.OPERATOR
elif token.subtype == TokenType.UNARY:
node = Node(NodeType.OPERATOR, subtype=NodeType.UNARY)
node.left = Node(NodeType.OPERATOR, subtype=token.value)
state = State.NAME
if current_node is None:
current_node = node
elif current_node.type == NodeType.NUMBER:
raise ValueError("Not a valid expression")
elif current_node.type == NodeType.OPERATOR:
if current_node.left is None:
current_node.left = node
node.parent = current_node
elif current_node.right is None:
current_node.right = node
node.parent = current_node
current_node = node
else:
raise ValueError("Not a valid expression")
elif token.type == TokenType.OPERATOR:
node = Node(NodeType.OPERATOR, subtype=token.subtype, value=token.value)
if current_node is None:
raise ValueError("Not a valid expression")
elif current_node.type in [NodeType.NUMBER, NodeType.OPERATOR, NodeType.FUNCALL]:
while current_node.parent is not None:
if PRECEDENCE[current_node.parent.subtype] < PRECEDENCE[node.subtype]:
node.parent = current_node.parent
if node.parent is not None:
node.parent.right = node
break
current_node = current_node.parent
current_node.parent = node
node.left = current_node
current_node = node
else:
raise ValueError("Not a valid expression")
state = State.NAME
elif token.type in [TokenType.SEMICOLON, TokenType.COMMA]:
break
i += 1
while current_node.parent is not None:
current_node = current_node.parent
return current_node, i - 1
def parse_let_statement(tokens: list[Token], start: int):
class LetStates:
(WAIT_LET, WAIT_SYMBOL, WAIT_EQUALS, WAIT_EXPR, WAIT_SEMICOLON, PARSE_END, *_) = range(100)
root_node = Node(NodeType.ASSIGNMENT)
state = LetStates.WAIT_LET
i = start
while i < len(tokens):
token = tokens[i]
if state == LetStates.WAIT_LET:
if token.type == TokenType.KEYWORD and token.subtype == Keyword.LET:
state = LetStates.WAIT_SYMBOL
else:
raise ParserError(f"Waited for let, got {token}")
elif state == LetStates.WAIT_SYMBOL:
if token.type == TokenType.SYMBOL:
node = Node(NodeType.SYMBOL, value=token.value)
root_node.left = node
state = LetStates.WAIT_EQUALS
else:
raise ParserError(f"Waited for symbol, got {token}")
elif state == LetStates.WAIT_EQUALS:
if token.type == TokenType.EQUALS:
state = LetStates.WAIT_EXPR
else:
raise ParserError(f"Waited for equals, got {token}")
elif state == LetStates.WAIT_EXPR:
node, i = parse_expr(tokens, i)
root_node.right = node
state = LetStates.WAIT_SEMICOLON
elif state == LetStates.WAIT_SEMICOLON:
if token.type == TokenType.SEMICOLON:
state = LetStates.PARSE_END
break
else:
raise ParserError(f"Waited for semicolon, got {token}")
i += 1
if state != LetStates.PARSE_END:
raise ParserError("Statement ended unexpectedly")
return root_node, i
def parse_function_call(tokens: list[Token], start: int):
class FuncStates:
(WAIT_SYMBOL, WAIT_LEFT_PAR, PARSING_EXPR, WAIT_SEMICOLON, PARSE_END, *_) = range(100)
root_node = Node(NodeType.FUNCALL)
state = FuncStates.WAIT_SYMBOL
i = start
args = []
arg = []
while i < len(tokens):
token = tokens[i]
if state == FuncStates.WAIT_SYMBOL:
if token.type == TokenType.SYMBOL:
root_node.left = Node(NodeType.SYMBOL, value=token.value)
state = FuncStates.WAIT_LEFT_PAR
else:
raise ParserError(f"Waited for symbol, got {token}")
elif state == FuncStates.WAIT_LEFT_PAR:
if token.type == TokenType.LEFT_PARENTHESIS:
state = FuncStates.PARSING_EXPR
else:
raise ParserError(f"Waited for left parenthesis, got {token}")
elif state == FuncStates.PARSING_EXPR:
if token.type == TokenType.COMMA:
node, _ = parse_expr(arg, 0)
args.append(node)
arg.clear()
elif token.type == TokenType.RIGHT_PARENTHESIS:
node, _ = parse_expr(arg, 0)
args.append(node)
root_node.right = Node(NodeType.ARGUMENTS, value=args)
state = FuncStates.WAIT_SEMICOLON
else:
arg.append(token)
elif state == FuncStates.WAIT_SEMICOLON:
if token.type == TokenType.SEMICOLON:
state = FuncStates.PARSE_END
break
else:
raise ParserError(f"Waited for semicolon, got {token}")
i += 1
if state != FuncStates.PARSE_END:
raise ParserError("Statement ended unexpectedly")
return root_node, i
def parse(tokens: list[Token]):
class ParseState:
(ANY, GOT_SYMBOL, *_) = range(100)
_statements = [
[Keyword.LET, TokenType.SYMBOL, TokenType.EQUALS, "EXPR", TokenType.SEMICOLON],
[TokenType.SYMBOL, TokenType.EQUALS, "EXPR", TokenType.SEMICOLON],
[TokenType.SYMBOL, TokenType.LEFT_PARENTHESIS, "ARGS", TokenType.RIGHT_PARENTHESIS, TokenType.SEMICOLON],
[Keyword.FN, TokenType.SYMBOL, TokenType.LEFT_PARENTHESIS, "ARGS", TokenType.RIGHT_PARENTHESIS, TokenType.LEFT_BRACE, ["STATEMENT"], TokenType.RIGHT_BRACE],
]
state = ParseState.ANY
statements = []
symbol = None
i = 0
while i < len(tokens):
token = tokens[i]
if state == ParseState.ANY:
if token.type == TokenType.KEYWORD:
if token.subtype == Keyword.LET:
node, i = parse_let_statement(tokens, i)
statements.append(node)
elif token.type == TokenType.SYMBOL:
state = ParseState.GOT_SYMBOL
elif state == ParseState.GOT_SYMBOL:
if token.type == TokenType.LEFT_PARENTHESIS:
node, i = parse_function_call(tokens, i - 1)
statements.append(node)
state = ParseState.ANY
else:
raise ParserError("oops...")
i += 1
return statements
|
