Class PeekStack

marimo/_ast/parse.py:735–761

Builtins don't have a peek, which is useful here.

class PeekStack(Generic[U]):
    """Builtins don't have a peek, which is useful here."""

    def __init__(self, iterable: Iterator[U]):
        self._iterable = iterable
        self._next: U | None = None
        self.last: U | None = None

    def __next__(self) -> U | None:
        if self._next:
            self.last = self._next
            self._next = None
        else:
            try:
                self.last = next(self._iterable)
            except StopIteration:
                self.last = None
        return self.last

    def peek(self) -> U | None:
        if self._next:
            return self._next
        try:
            self._next = next(self._iterable)
        except StopIteration:
            self._next = None
        return self._next


def _maybe_kwargs(