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import re
KEYWORDS = [
"class",
"constructor",
"function",
"method",
"field",
"static",
"var",
"int",
"char",
"boolean",
"void",
"true",
"false",
"null",
"this",
"let",
"do",
"if",
"else",
"while",
"return",
]
SYMBOLS = "{}()[].,;+-*/&|<>=~"
TOKEN_TYPES = ["keyword", "symbol", "integer", "string", "identifier"]
class Token:
def __init__(self, type: str, token: str, line_no: int, column: int):
"""A token in JACK."""
self.type = type
self.token = token
self.line_no = line_no
self.column = column
@classmethod
def from_line(cls, line: str, line_no: int, column: int):
"""Extract first token from line and return it as an instance of Token."""
if not line:
return None
if line[0] in SYMBOLS:
return Token("symbol", line[0], line_no, column)
int_match = re.match("([0-9]+)", line)
if int_match is not None:
return Token("integer", int_match.group(1), line_no, column)
str_match = re.match('(".*")', line)
if str_match is not None:
return Token("string", str_match.group(1), line_no, column)
# keyword or identifier
kwid_match = re.match("([_A-Za-z][_A-Za-z0-9]*)", line)
if kwid_match is not None:
kwid = kwid_match.group(1)
type = "identifier"
if kwid in KEYWORDS:
type = "keyword"
return Token(type, kwid, line_no, column)
return None
def length(self) -> int:
return len(self.token)
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