reasoning-gym/reasoning_gym/code/contrib/bfit/Compiler/Lexical_analyzer.py
2025-01-30 15:42:11 +01:00

183 lines
7 KiB
Python

import re
from .Token import Token
from .Optimizer import optimize
class LexicalErrorException(Exception):
pass
def analyze(text):
"""
:returns list of tokens in the text
raises exception in case of lexical error
"""
rules = [
('\s+', Token.WHITESPACE),
('void', Token.VOID),
('int', Token.INT),
('bool', Token.INT), # treat bool as int
('char', Token.INT), # treat char as int
('true', Token.TRUE),
('false', Token.FALSE),
('&&', Token.AND),
('\|\|', Token.OR),
('\!', Token.NOT),
('return', Token.RETURN),
('if', Token.IF),
('else', Token.ELSE),
('while', Token.WHILE),
('for', Token.FOR),
('do', Token.DO),
('print', Token.PRINT),
('switch', Token.SWITCH),
('case', Token.CASE),
('default', Token.DEFAULT),
('break', Token.BREAK),
('continue', Token.CONTINUE), # todo
(':', Token.COLON),
(';', Token.SEMICOLON),
(',', Token.COMMA),
('\(', Token.LPAREN),
('\)', Token.RPAREN),
('\{', Token.LBRACE),
('\}', Token.RBRACE),
('\[', Token.LBRACK),
('\]', Token.RBRACK),
('=|\+=|-=|\*=|/=|%=|<<=|>>=|&=|\|=|\^=', Token.ASSIGN),
('\?', Token.TERNARY),
('<=|>=|==|!=|<|>', Token.RELOP),
('\+\+', Token.INCREMENT),
('--', Token.DECREMENT),
('\+|-|\*|/|%', Token.BINOP),
('\*\*|//|%%', Token.UNARY_MULTIPLICATIVE),
('<<|>>', Token.BITWISE_SHIFT),
('~', Token.BITWISE_NOT),
('&', Token.BITWISE_AND),
('\|', Token.BITWISE_OR),
('\^', Token.BITWISE_XOR),
('([a-zA-Z_][a-zA-Z0-9_]*)', Token.ID),
('(\d+)', Token.NUM),
('(0x[A-Fa-f\d]+)', Token.NUM), # hexadecimal number
('(0o[0-7]+)', Token.NUM), # octal number
('(0b[01]+)', Token.NUM), # binary number
(r'\"(\\\"|[^"])*"', Token.STRING),
(r'\'(\\\'|(\\)?[^\'])\'', Token.CHAR),
('//.*(\\n|$)', Token.COMMENT),
(r'/\*[\s\S]*?\*/', Token.COMMENT), # multiline comments
('.', Token.UNIDENTIFIED)
]
rules = [(re.compile(r), t) for r, t in rules]
tokens = []
# create a mapping of [line number] to [offset of that line from the beginning of the text]
newline = re.compile('\n')
lines = [0] + [m.end() for m in re.finditer(newline, text)]
i = 0
while i < len(text):
current_matches = []
for regex, token_type in rules:
m = regex.match(text, i)
if m:
current_matches.append((m, token_type))
# pick the token that fits the longest match
# if tie - pick the one defined first in the rules list
longest_match, max_i, matched_token = None, i, None
for match, token_type in current_matches:
if match.end() > max_i:
longest_match, max_i, matched_token = match, match.end(), token_type
# calculate line and column
line, column = None, None
for line_idx in range(len(lines)-1):
if lines[line_idx] <= longest_match.start() < lines[line_idx+1]:
line, column = line_idx+1, (longest_match.start() - lines[line_idx])+1 # humans count from 1 :)
break
if not line:
line, column = len(lines), (longest_match.start() - lines[-1])+1
if matched_token in [Token.COMMENT, Token.WHITESPACE]:
pass # do nothing
elif matched_token == Token.UNIDENTIFIED:
raise LexicalErrorException("Unidentified Character '%s' (line %s column %s)" % (text[i], line, column))
elif matched_token in [Token.STRING, Token.CHAR]:
# remove quotes at beginning and end, un-escape characters
tokens.append(Token(matched_token, line, column, longest_match.group()[1:-1].encode("utf8").decode("unicode_escape")))
elif matched_token in [Token.NUM, Token.ID, Token.BINOP, Token.RELOP, Token.ASSIGN, Token.UNARY_MULTIPLICATIVE, Token.BITWISE_SHIFT]:
tokens.append(Token(matched_token, line, column, longest_match.group()))
else:
tokens.append(Token(matched_token, line, column))
i = longest_match.end()
return tokens
def tests():
def test1():
# test token priorities: INT should not be confused with ID even if ID contains "int"
text = "my international int ; int; pints; international;"
res = analyze(text)
expected = [Token.ID, Token.ID, Token.INT, Token.SEMICOLON, Token.INT, Token.SEMICOLON, Token.ID,
Token.SEMICOLON, Token.ID, Token.SEMICOLON]
assert len(res) == len(expected) and all(res[i].type == expected[i] for i in range(len(res)))
def test2():
text = "true !||!false falsek k||y+-a&&x"
res = analyze(text)
expected = [Token.TRUE, Token.NOT, Token.OR, Token.NOT, Token.FALSE, Token.ID, Token.ID, Token.OR, Token.ID,
Token.BINOP, Token.BINOP, Token.ID, Token.AND, Token.ID]
assert len(res) == len(expected) and all(res[i].type == expected[i] for i in range(len(res)))
def test3():
text = "1+2"
tokens = analyze(text)
expected = [Token.NUM, Token.BINOP, Token.NUM]
assert len(tokens) == len(expected) and all(tokens[i].type == expected[i] for i in range(len(tokens)))
optimize(tokens)
assert len(tokens) == 1 and tokens[0].type == Token.NUM and tokens[0].data == "3"
text = "1+2+3"
tokens = analyze(text)
expected = [Token.NUM, Token.BINOP, Token.NUM, Token.BINOP, Token.NUM]
assert len(tokens) == len(expected) and all(tokens[i].type == expected[i] for i in range(len(tokens)))
optimize(tokens)
assert len(tokens) == 1 and tokens[0].type == Token.NUM and tokens[0].data == "6"
# make sure it is not optimized to 9 (3*3)
text = "1+2*3"
tokens = analyze(text)
expected = [Token.NUM, Token.BINOP, Token.NUM, Token.BINOP, Token.NUM]
assert len(tokens) == len(expected) and all(tokens[i].type == expected[i] for i in range(len(tokens)))
optimize(tokens)
assert len(tokens) == 1 and tokens[0].type == Token.NUM and tokens[0].data == "7"
# test all arithmetic operations
text = "(1+2*3/6)+(1%3)*(6-1)"
tokens = analyze(text)
expected = [Token.LPAREN, Token.NUM, Token.BINOP, Token.NUM, Token.BINOP, Token.NUM, Token.BINOP, Token.NUM,
Token.RPAREN, Token.BINOP, Token.LPAREN, Token.NUM, Token.BINOP, Token.NUM, Token.RPAREN,
Token.BINOP, Token.LPAREN, Token.NUM, Token.BINOP, Token.NUM, Token.RPAREN]
assert len(tokens) == len(expected) and all(tokens[i].type == expected[i] for i in range(len(tokens)))
optimize(tokens)
assert tokens[1].data == "2" and tokens[5].data == "1" and tokens[9].data == "5"
# todo find a better way to test?
test1()
test2()
test3()
if __name__ == '__main__':
tests()