Class Struct

caffe2/python/schema.py:369–675

Represents a named list of fields sharing the same domain.

class Struct(Field):
    """Represents a named list of fields sharing the same domain.
    """

    __slots__: Sequence[str] = ("fields", "_frozen")

    def __init__(self, *fields):
        """ fields is a list of tuples in format of (name, field). The name is
        a string of nested name, e.g., `a`, `a:b`, `a:b:c`. For example

        Struct(
          ('a', Scalar()),
          ('b:c', Scalar()),
          ('b:d:e', Scalar()),
          ('b', Struct(
            ('f', Scalar()),
          )),
        )

        is equal to

        Struct(
          ('a', Scalar()),
          ('b', Struct(
            ('c', Scalar()),
            ('d', Struct(('e', Scalar()))),
            ('f', Scalar()),
          )),
        )
        """
        for field in fields:
            assert len(field) == 2
            assert field[0], 'Field names cannot be empty'
            assert field[0] != 'lengths', (
                'Struct cannot contain a field named `lengths`.'
            )
        fields = [(name, _normalize_field(field)) for name, field in fields]
        self.fields = OrderedDict()
        for name, field in fields:
            if FIELD_SEPARATOR in name:
                name, field = self._struct_from_nested_name(name, field)
            if name not in self.fields:
                self.fields[name] = field
                continue
            if (
                    not isinstance(field, Struct) or
                    not isinstance(self.fields[name], Struct)
            ):
                raise ValueError('Duplicate field name: %s' % name)
            self.fields[name] = self.fields[name] + field
        for id, (_, field) in enumerate(self.fields.items()):
            field._set_parent(self, id)
        super().__init__(self.fields.values())
        self._frozen = True

    def _struct_from_nested_name(self, nested_name, field):
        def create_internal(nested_name, field):
            names = nested_name.split(FIELD_SEPARATOR, 1)