pep-484 - SQL column operations

note we are taking out the
ColumnOperartors[SQLCoreOperations] thing; not really clear
why that was needed and at the moment it seems I was likely
confused.

Change-Id: I834b75f9b44f91b97e29f2e1a7b1029bd910e0a1

1 files changed, 45 insertions, 1 deletions

diff --git a/lib/sqlalchemy/sql/_typing.py b/lib/sqlalchemy/sql/_typing.py
index 69e4645fa..389f7e8d0 100644
--- a/lib/sqlalchemy/sql/_typing.py
+++ b/lib/sqlalchemy/sql/_typing.py
@@ -1,14 +1,58 @@
 from __future__ import annotations
 
+from typing import Any
 from typing import Type
+from typing import TYPE_CHECKING
+from typing import TypeVar
 from typing import Union
 
 from . import roles
+from .. import util
 from ..inspection import Inspectable
 
+if TYPE_CHECKING:
+    from .elements import quoted_name
+    from .schema import DefaultGenerator
+    from .schema import Sequence
+    from .selectable import FromClause
+    from .selectable import NamedFromClause
+    from .selectable import TableClause
+    from .sqltypes import TupleType
+    from .type_api import TypeEngine
+    from ..util.typing import TypeGuard
+
+_T = TypeVar("_T", bound=Any)
+
 _ColumnsClauseElement = Union[
-    roles.ColumnsClauseRole, Type, Inspectable[roles.HasClauseElement]
+    roles.ColumnsClauseRole,
+    Type,
+    Inspectable[roles.HasColumnElementClauseElement],
 ]
 _FromClauseElement = Union[
     roles.FromClauseRole, Type, Inspectable[roles.HasFromClauseElement]
 ]
+
+_ColumnExpression = Union[
+    roles.ExpressionElementRole[_T],
+    Inspectable[roles.HasColumnElementClauseElement],
+]
+
+_PropagateAttrsType = util.immutabledict[str, Any]
+
+_TypeEngineArgument = Union[Type["TypeEngine[_T]"], "TypeEngine[_T]"]
+
+
+def is_named_from_clause(t: FromClause) -> TypeGuard[NamedFromClause]:
+    return t.named_with_column
+
+
+def has_schema_attr(t: FromClause) -> TypeGuard[TableClause]:
+    return hasattr(t, "schema")
+
+
+def is_quoted_name(s: str) -> TypeGuard[quoted_name]:
+    return hasattr(s, "quote")
+
+
+def is_tuple_type(t: TypeEngine[Any]) -> TypeGuard[TupleType]:
+    return t._is_tuple_type