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from lexer import TokenType
class Expr:
def accept(self, visitor):
raise Exception("needs to be implemented")
class Literal:
def __init__(self, value):
self.value = value
def accept(self, visitor):
visitor.visitLiteral(self)
def __str__(self):
return f"{self.value}"
class Type:
def __init__(self, name):
self.name = name
def __str__(self):
return self.name
class Symbol:
def __init__(self, name):
self.name = name
def accept(self, visitor):
visitor.visitSymbol(self)
def __str__(self):
return f"'{self.name}"
class List:
def __init__(self, args):
self.args = args
def accept(self, visitor):
visitor.visitNary(self)
def __str__(self):
return "(" + " ".join(f"{arg}" for arg in self.args) + ")"
def parseExpression(token, prev, tokens):
idx = 0
args = []
prev = token
while tokens[idx].type_ != TokenType.CLOSE_PAREN:
token = tokens[idx]
inc = 1
if token.type_ == TokenType.OPEN_PAREN:
expr, inc = parseExpression(token, prev, tokens[idx+1:])
args.append(expr)
elif token.type_ in (TokenType.STRING, TokenType.TRUE, TokenType.FALSE, TokenType.INT, TokenType.FLOAT):
expr, inc = parseLiteral(token, prev, tokens[idx+1:])
args.append(expr)
elif token.type_ in (TokenType.INT_TYPE, TokenType.FLOAT_TYPE, TokenType.STRING_TYPE, TokenType.ANY_TYPE):
expr, inc = parseType(token, prev, tokens[idx+1:])
args.append(expr)
else:
expr, inc = parseSymbol(token, prev, tokens[idx+1:])
args.append(expr)
idx += inc
prev = token
return Expr.List(args), idx + 2 # parens
def parseSymbol(token, prev, tokens):
return Expr.Symbol(token.text), 1
def parseLiteral(token, prev, tokens):
return Expr.Literal(token.value), 1
def parseType(token, prev, tokens):
return Expr.Type(token.text), 1
def parse(tokens):
idx = 0
prev = None
exprs = []
while tokens[idx].type_ != TokenType.EOF:
token = tokens[idx]
counter = 1
if token.type_ == TokenType.OPEN_PAREN:
expr, counter = parseExpression(token, prev, tokens[idx+1:])
exprs.append(expr)
elif token.type_ in (TokenType.FALSE, TokenType.TRUE, TokenType.STRING, TokenType.INT, TokenType.FLOAT):
lit, counter = parseLiteral(token, prev, tokens[idx+1:])
exprs.append(lit)
elif token.type_ in (TokenType.INT_TYPE, TokenType.FLOAT_TYPE, TokenType.STRING_TYPE, TokenType.ANY_TYPE):
typ, counter = parseType(token, prev, tokens[idx+1:])
exprs.append(typ)
else:
sym, counter = parseSymbol(token, prev, tokens[idx+1:])
exprs.append(sym)
idx += counter
prev = token
return exprs
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