def advance(self): self.pos += 1 if self.pos > len(self.text) - 1: self.current_char = None else: self.current_char = self.text[self.pos]
if self.current_char.isdigit(): return Token(INTEGER, self.integer())
# Lexer class class Lexer: def __init__(self, text): self.text = text self.pos = 0 self.current_char = self.text[self.pos] compiler design book of aa puntambekar pdf 71 2021
self.error()
if self.current_char == '-': self.advance() return Token(MINUS, '-') def advance(self): self
Here is sample code for lexical analyzer
def integer(self): result = '' while self.current_char is not None and self.current_char.isdigit(): result += self.current_char self.advance() return int(result) compiler design book of aa puntambekar pdf 71 2021
# Example usage lexer = Lexer('2 + 3') token = lexer.get_next_token()