Class ParseMachine

invoke/parser/parser.py:205–455

class ParseMachine(StateMachine):
    initial_state = "context"

    state("context", enter=["complete_flag", "complete_context"])
    state("unknown", enter=["complete_flag", "complete_context"])
    state("end", enter=["complete_flag", "complete_context"])

    transition(from_=("context", "unknown"), event="finish", to="end")
    transition(
        from_="context",
        event="see_context",
        action="switch_to_context",
        to="context",
    )
    transition(
        from_=("context", "unknown"),
        event="see_unknown",
        action="store_only",
        to="unknown",
    )

    def changing_state(self, from_: str, to: str) -> None:
        debug("ParseMachine: {!r} => {!r}".format(from_, to))

    def __init__(
        self,
        initial: "ParserContext",
        contexts: Lexicon,
        ignore_unknown: bool,
    ) -> None:
        # Initialize
        self.ignore_unknown = ignore_unknown
        self.initial = self.context = copy.deepcopy(initial)
        debug("Initialized with context: {!r}".format(self.context))
        self.flag = None
        self.flag_got_value = False
        self.result = ParseResult()
        self.contexts = copy.deepcopy(contexts)
        debug("Available contexts: {!r}".format(self.contexts))
        # In case StateMachine does anything in __init__
        super().__init__()

    @property
    def waiting_for_flag_value(self) -> bool:
        # Do we have a current flag, and does it expect a value (vs being a
        # bool/toggle)?
        takes_value = self.flag and self.flag.takes_value
        if not takes_value:
            return False
        # OK, this flag is one that takes values.
        # Is it a list type (which has only just been switched to)? Then it'll
        # always accept more values.
        # TODO: how to handle somebody wanting it to be some other iterable
        # like tuple or custom class? Or do we just say unsupported?
        if self.flag.kind is list and not self.flag_got_value:
            return True
        # Not a list, okay. Does it already have a value?
        has_value = self.flag.raw_value is not None