Merge the Member and Param, make GetArg on Callable return Params

Author: msullivan

spec-draft.rst

@@ -153,12 +153,12 @@ Methods are returned as callables using the new ``Param`` based extended callabl
 
 TODO: What do we do about decorators in general, *at runtime*... This seems pretty cursed. We can probably sometimes evaluate them, if there are annotations at runtime.
 
-We also have helpers for extracting those names; they are all definable in terms of ``GetArg``.
-(These names are too long -- but we can't do ``Type``. I kind of want to do the *longer* ``MemberName``?)
+We also have helpers for extracting those names; they are all definable in terms of ``GetArg``. (Some of them are shared with ``Param``, discussed below.)
+(These names are too long -- but we can't do ``Type``.)
 
-* ``GetName[T: Member]``
-* ``GetType[T: Member]``
-* ``GetQuals[T: Member]``
+* ``GetName[T: Member | Param]``
+* ``GetType[T: Member | Param]``
+* ``GetQuals[T: Member | Param]``
 * ``GetDefiner[T: Member]``
 
 * ``NewProtocolWithBases[Bases, Ps: tuple[Member]]`` - A variant that allows specifying bases too. (UNIMPLEMENTED)
@@ -174,14 +174,10 @@ We also have helpers for extracting those names; they are all definable in terms
 Callable inspection and creation
 --------------------------------
 
-* TODO: Should ``GetArg`` on a callable automatically convert ``[int, str]`` or whatever into something using ``Param``? Or should a separate operator be needed?
+``Callable`` types always have their arguments exposed in the extended Callable format discussed above.
 
-* ``GetParamName[T: Param]``
-* ``GetParamType[T: Param]``
-* ``GetParamQuals[T: Param]``
+The names, type, and qualifiers share getter operations with ``Member``.
 
-This is unsatisfying; maybe they all need to be just ``ParamName`` and also ``MemberName`` above.
-We could also merge the getters for ``Param`` and ``Member``.
 
 ----
 

tests/test_type_eval.py

@@ -29,6 +29,7 @@
     Length,
     Member,
     NewProtocol,
+    Param,
     SpecialFormEllipsis,
     StrConcat,
     StrSlice,
@@ -349,7 +350,8 @@ def test_eval_getargs():
     assert args == tuple[Any, Any]
 
 
-def test_eval_getarg_callable():
+@unittest.skip
+def test_eval_getarg_callable_old():
     # oh hmmmmmmm -- yeah maybe callable could be fully bespoke if we
     # disallowed putting Callable here...!
     t = Callable[[int, str], str]
@@ -377,6 +379,38 @@ def test_eval_getarg_callable():
     assert args == Any
 
 
+def test_eval_getarg_callable():
+    t = Callable[[int, str], str]
+    args = eval_typing(GetArg[t, Callable, 0])
+    assert (
+        args
+        == tuple[
+            Param[Literal[None], int, Never], Param[Literal[None], str, Never]
+        ]
+    )
+
+    t = Callable[int, str]
+    args = eval_typing(GetArg[t, Callable, 0])
+    assert args == tuple[Param[Literal[None], int, Never]]
+
+    t = Callable[[], str]
+    args = eval_typing(GetArg[t, Callable, 0])
+    assert args == tuple[()]
+
+    # XXX: Is this what we want? Or should it be *args, **kwargs
+    t = Callable[..., str]
+    args = eval_typing(GetArg[t, Callable, 0])
+    assert args == SpecialFormEllipsis
+
+    t = Callable
+    args = eval_typing(GetArg[t, Callable, 0])
+    assert args == SpecialFormEllipsis
+
+    t = Callable
+    args = eval_typing(GetArg[t, Callable, 1])
+    assert args == Any
+
+
 def test_eval_getarg_tuple():
     t = tuple[int, ...]
     args = eval_typing(GetArg[t, tuple, 1])

typemap/type_eval/_eval_operators.py

@@ -513,6 +513,22 @@ def _eval_GetAttr(tp, prop, *, ctx):
         return typing.Never
 
 
+def _fix_callable_args(base, args):
+    idx = FUNC_LIKES[base]
+    if idx >= len(args):
+        return args
+    args = list(args)
+    special = _fix_type(args[idx])
+    if typing.get_origin(special) is tuple:
+        args[idx] = tuple[
+            *[
+                t if isinstance(t, Param) else Param[typing.Literal[None], t]
+                for t in typing.get_args(special)
+            ]
+        ]
+    return tuple(args)
+
+
 def _get_raw_args(tp, base_head, ctx) -> typing.Any:
     evaled = _eval_types(tp, ctx)
 
@@ -521,7 +537,11 @@ def _get_raw_args(tp, base_head, ctx) -> typing.Any:
         return None
 
     if tp_head is base_head:
-        return typing.get_args(evaled)
+        args = typing.get_args(evaled)
+        if _is_method_like(tp):
+            args = _fix_callable_args(base_head, args)
+
+        return args
 
     # Scan the fully-annotated MRO to find the base
     box = _apply_generic.box(tp)
@@ -544,10 +564,12 @@ def _get_args(tp, base, ctx) -> typing.Any:
 def _fix_type(tp):
     """Fix up a type getting returned from GetArg
 
-    In particular, this means turning a list into a tuple of the list
-    elements and turning ... into SpecialFormEllipsis.
+    In particular, this means turning a list into a tuple of the
+    Paramified list elements and turning ... into SpecialFormEllipsis.
+
     """
     if isinstance(tp, (tuple, list)):
+        # XXX: Can we always do this or is it a problem
         return tuple[*tp]
     elif tp is ...:
         return SpecialFormEllipsis
@@ -714,13 +736,16 @@ def _add_quals(typ, quals):
     return typ
 
 
+FUNC_LIKES = {
+    GenericCallable: 0,
+    collections.abc.Callable: 0,
+    staticmethod: 0,
+    classmethod: 1,
+}
+
+
 def _is_method_like(typ):
-    return typing.get_origin(typ) in (
-        GenericCallable,
-        collections.abc.Callable,
-        staticmethod,
-        classmethod,
-    )
+    return typing.get_origin(typ) in FUNC_LIKES
 
 
 @type_eval.register_evaluator(NewProtocol)

typemap/typing.py

@@ -34,25 +34,25 @@ class GenericCallable[
 
 
 class Member[N: str, T, Q: MemberQuals = typing.Never, D = typing.Never]:
-    pass
-
-
-type GetName[T: Member] = GetArg[T, Member, 0]  # type: ignore[valid-type]
-type GetType[T: Member] = GetArg[T, Member, 1]  # type: ignore[valid-type]
-type GetQuals[T: Member] = GetArg[T, Member, 2]  # type: ignore[valid-type]
-type GetDefiner[T: Member] = GetArg[T, Member, 3]  # type: ignore[valid-type]
+    name: N
+    typ: T
+    quals: Q
+    definer: D
 
 
 ParamQuals = typing.Literal["*", "**", "="]
 
 
 class Param[N: str | None, T, Q: ParamQuals = typing.Never]:
-    pass
+    name: N
+    typ: T
+    quals: Q
 
 
-type GetParamName[T: Param] = GetArg[T, Param, 0]  # type: ignore[valid-type]
-type GetParamType[T: Param] = GetArg[T, Param, 1]  # type: ignore[valid-type]
-type GetParamQuals[T: Param] = GetArg[T, Param, 2]  # type: ignore[valid-type]
+type GetName[T: Member | Param] = GetAttr[T, typing.Literal["name"]]
+type GetType[T: Member | Param] = GetAttr[T, typing.Literal["typ"]]
+type GetQuals[T: Member | Param] = GetAttr[T, typing.Literal["quals"]]
+type GetDefiner[T: Member] = GetAttr[T, typing.Literal["definer"]]
 
 
 class Attrs[T]: