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from .structs import *
from .exceptions import ParseError
def parseExpression(token, prev, tokens):
idx = 0
args = []
prev = token
while tokens[idx].type_ != TokenType.CLOSE_PAREN:
token = tokens[idx]
if token.type_ == TokenType.EOF:
raise ParseError("uneven parens: not enough closing!", token.line)
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_ == TokenType.COLON:
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(args), idx + 2 # parens
def parseSymbol(token, prev, tokens):
return Symbol(token.text, token.line), 1
def parseLiteral(token, prev, tokens):
if token.type_ == TokenType.STRING:
return String(token.value), 1
elif token.type_ == TokenType.INT:
return Int(token.value), 1
elif token.type_ == TokenType.FLOAT:
return Float(token.value), 1
elif token.type_ in (TokenType.TRUE, TokenType.FALSE):
return Bool(token.value), 1
else:
return Literal(token.value), 1
def parseType(token, prev, tokens):
# if the next token is a symbol, combine for a type
if len(tokens) > 0 and tokens[0].type_ == TokenType.SYMBOL:
return Type(f":{tokens[0].text}"), 2
elif tokens[0].type_ == TokenType.OPEN_BRACKET:
# only format currently supported:
# [ <type> ]
if tokens[1].type_ != TokenType.COLON:
raise ParseError("invalid type definition (expecting colon)", tokens[1].line)
typ, counter = parseType(tokens[1], tokens[0], tokens[2:])
if tokens[1+counter].type_ != TokenType.CLOSE_BRACKET:
raise ParseError("invalid type definition (expecting close bracket)", tokens[1+counter].line)
return Type(f":[]", typ), counter + 3
else:
raise ParseError("invalid type definition!", tokens[0].line)
def parse(tokens):
idx = 0
prev = None
exprs = []
while tokens[idx].type_ != TokenType.EOF:
token = tokens[idx]
counter = 1
if token.type_ == TokenType.CLOSE_PAREN:
raise ParseError("uneven parens: too many closing!", token.line)
elif 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_ == TokenType.COLON:
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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