def value_from_scanner(s: Scanner) -> Value:
"""Recursive call for converting a stream of tokens into a value."""
if s.try_pop(TokenKind.OPAREN):
elements = []
must_end = False
while True:
if s.try_pop(TokenKind.CPAREN):
break
if must_end:
s.pop_or_error(TokenKind.CPAREN)
break
elements.append(value_from_scanner(s))
must_end = not s.try_pop(TokenKind.COMMA)
return Value.make_tuple(tuple(elements))
if s.try_pop(TokenKind.OBRACK):
elements = []
must_end = False
while True:
if s.try_pop(TokenKind.CBRACK):
break
if must_end:
s.pop_or_error(TokenKind.CBRACK)
break
elements.append(value_from_scanner(s))
must_end = not s.try_pop(TokenKind.COMMA)
return Value.make_array(tuple(elements))
if s.try_pop_keyword(Keyword.BITS) or s.try_pop_keyword(Keyword.UN):
return _bit_value_from_scanner(s, signed=False)
if s.try_pop_keyword(Keyword.BITS) or s.try_pop_keyword(Keyword.SN):
return _bit_value_from_scanner(s, signed=True)
if s.peek().is_type_keyword():
type_ = s.pop()
s.drop_or_error(TokenKind.COLON)
value_tok = s.pop_or_error(TokenKind.NUMBER)
signedness, bit_count = scanner_mod.TYPE_KEYWORDS_TO_SIGNEDNESS_AND_BITS[
type_.value]
constructor = Value.make_sbits if signedness else Value.make_ubits
return constructor(
bit_count=bit_count,
value=ast_helpers.get_token_value_as_int(value_tok))
raise ScanError(s.peek().span.start,
'Unexpected token in value; found {}'.format(s.peek().kind))
def _bit_value_from_scanner(s: Scanner, signed: bool) -> Value:
s.drop_or_error(TokenKind.OBRACK)
bit_count_tok = s.pop_or_error(TokenKind.NUMBER)
s.drop_or_error(TokenKind.CBRACK)
s.drop_or_error(TokenKind.COLON)
value_tok = s.pop_or_error(TokenKind.NUMBER)
constructor = Value.make_sbits if signed else Value.make_ubits
return constructor(
bit_count=ast_helpers.get_token_value_as_int(bit_count_tok),
value=ast_helpers.get_token_value_as_int(value_tok))