def next_token(self):
token = Token()
self.skip_whitespaces()
skip_read_char = False
if self.ch == '+':
if self.peek_char() == '+':
self.read_char()
token.type = TokenType.PLUSPLUS
token.literal = '++'
else:
token.type = TokenType.PLUS
token.literal = self.ch
elif self.ch == '-':
token.type = TokenType.MINUS
token.literal = self.ch
elif self.ch == '/':
if self.peek_char() == '*':
self.read_char()
token.type = TokenType.START_COMMENT
token.literal = '/*'
else:
token.type = TokenType.SLASH
token.literal = self.ch
elif self.ch == '*':
if self.peek_char() == '/':
self.read_char()
token.type = TokenType.END_COMMENT
token.literal = '*/'
else:
token.type = TokenType.ASTERISK
token.literal = self.ch
elif self.ch == '>':
if self.peek_char() == '=':
self.read_char()
token.type = TokenType.GTE
token.literal = ">="
else:
token.type = TokenType.GT
token.literal = self.ch
elif self.ch == '<':
if self.peek_char() == '=':
self.read_char()
token.type = TokenType.LTE
token.literal = "<="
else:
token.type = TokenType.LT
token.literal = self.ch
elif self.ch == ';':
token.type = TokenType.SEMICOLON
token.literal = self.ch
elif self.ch == '(':
token.type = TokenType.LPAREN
token.literal = self.ch
elif self.ch == ')':
token.type = TokenType.RPAREN
token.literal = self.ch
elif self.ch == '{':
token.type = TokenType.LBRACE
token.literal = self.ch
elif self.ch == '}':
token.type = TokenType.RBRACE
token.literal = self.ch
elif self.ch == ',':
token.type = TokenType.COMMA
token.literal = self.ch
elif self.ch == 0:
token.type = TokenType.EOF
token.literal = self.ch
elif self.ch == '"':
token.type = TokenType.STRING
token.literal = self.read_string()
elif self.ch == '[':
token.type = TokenType.LBRACKET
token.literal = self.ch
elif self.ch == ']':
token.type = TokenType.RBRACKET
token.literal = self.ch
elif self.ch == ':':
token.type = TokenType.COLON
token.literal = self.ch
elif self.ch == '.':
token.type = TokenType.DOT
token.literal = self.ch
elif self.ch == '=':
if self.peek_char() == '=':
self.read_char()
token.type = TokenType.EQ
token.literal = '=='
else:
token.type = TokenType.ASSIGN
token.literal = self.ch
elif self.ch == '!':
if self.peek_char() == '=':
self.read_char()
token.type = TokenType.NOT_EQ
token.literal = '!='
else:
token.type = TokenType.BANG
token.literal = '!'
else:
if self.is_letter():
token.literal = self.read_ident()
token.type = self.lookup_ident(token.literal)
skip_read_char = True
elif self.is_digit():
token.literal = self.read_number()
if '.' in token.literal:
token.type = TokenType.FLOAT
else:
token.type = TokenType.INT
skip_read_char = True
else:
token.type = TokenType.ILLEGAL
token.literal = ''
if not skip_read_char:
self.read_char()
return token
