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ast: allow overriding Value operators.

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Vegard Storheil Eriksen 2023-10-05 21:16:33 +02:00 committed by Catherine
parent 1c3227d956
commit 879601380d
3 changed files with 59 additions and 22 deletions
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67
amaranth/hdl/ast.py
View file

@ -156,6 +156,25 @@ def signed(width):
return Shape(width, signed=True) return Shape(width, signed=True)
def _overridable_by_reflected(method_name):
"""Allow overriding the decorated method.
Allows :class:`ValueCastable` to override the decorated method by implementing
a reflected method named ``method_name``. Intended for operators, but
also usable for other methods that have a reflected counterpart.
"""
def decorator(f):
@functools.wraps(f)
def wrapper(self, other):
if isinstance(other, ValueCastable) and hasattr(other, method_name):
res = getattr(other, method_name)(self)
if res is not NotImplemented:
return res
return f(self, other)
return wrapper
return decorator
class Value(metaclass=ABCMeta): class Value(metaclass=ABCMeta):
@staticmethod @staticmethod
def cast(obj): def cast(obj):
@ -195,26 +214,31 @@ class Value(metaclass=ABCMeta):
def __neg__(self): def __neg__(self):
return Operator("-", [self]) return Operator("-", [self])
@_overridable_by_reflected("__radd__")
def __add__(self, other): def __add__(self, other):
return Operator("+", [self, other]) return Operator("+", [self, other], src_loc_at=1)
def __radd__(self, other): def __radd__(self, other):
return Operator("+", [other, self]) return Operator("+", [other, self])
@_overridable_by_reflected("__rsub__")
def __sub__(self, other): def __sub__(self, other):
return Operator("-", [self, other]) return Operator("-", [self, other], src_loc_at=1)
def __rsub__(self, other): def __rsub__(self, other):
return Operator("-", [other, self]) return Operator("-", [other, self])
@_overridable_by_reflected("__rmul__")
def __mul__(self, other): def __mul__(self, other):
return Operator("*", [self, other]) return Operator("*", [self, other], src_loc_at=1)
def __rmul__(self, other): def __rmul__(self, other):
return Operator("*", [other, self]) return Operator("*", [other, self])
@_overridable_by_reflected("__rmod__")
def __mod__(self, other): def __mod__(self, other):
return Operator("%", [self, other]) return Operator("%", [self, other], src_loc_at=1)
def __rmod__(self, other): def __rmod__(self, other):
return Operator("%", [other, self]) return Operator("%", [other, self])
@_overridable_by_reflected("__rfloordiv__")
def __floordiv__(self, other): def __floordiv__(self, other):
return Operator("//", [self, other]) return Operator("//", [self, other], src_loc_at=1)
def __rfloordiv__(self, other): def __rfloordiv__(self, other):
return Operator("//", [other, self]) return Operator("//", [other, self])
@ -224,46 +248,57 @@ class Value(metaclass=ABCMeta):
# by a signed value to make sure the shift amount can always be interpreted as # by a signed value to make sure the shift amount can always be interpreted as
# an unsigned value. # an unsigned value.
raise TypeError("Shift amount must be unsigned") raise TypeError("Shift amount must be unsigned")
@_overridable_by_reflected("__rlshift__")
def __lshift__(self, other): def __lshift__(self, other):
other = Value.cast(other) other = Value.cast(other)
other.__check_shamt() other.__check_shamt()
return Operator("<<", [self, other]) return Operator("<<", [self, other], src_loc_at=1)
def __rlshift__(self, other): def __rlshift__(self, other):
self.__check_shamt() self.__check_shamt()
return Operator("<<", [other, self]) return Operator("<<", [other, self])
@_overridable_by_reflected("__rrshift__")
def __rshift__(self, other): def __rshift__(self, other):
other = Value.cast(other) other = Value.cast(other)
other.__check_shamt() other.__check_shamt()
return Operator(">>", [self, other]) return Operator(">>", [self, other], src_loc_at=1)
def __rrshift__(self, other): def __rrshift__(self, other):
self.__check_shamt() self.__check_shamt()
return Operator(">>", [other, self]) return Operator(">>", [other, self])
@_overridable_by_reflected("__rand__")
def __and__(self, other): def __and__(self, other):
return Operator("&", [self, other]) return Operator("&", [self, other], src_loc_at=1)
def __rand__(self, other): def __rand__(self, other):
return Operator("&", [other, self]) return Operator("&", [other, self])
@_overridable_by_reflected("__rxor__")
def __xor__(self, other): def __xor__(self, other):
return Operator("^", [self, other]) return Operator("^", [self, other], src_loc_at=1)
def __rxor__(self, other): def __rxor__(self, other):
return Operator("^", [other, self]) return Operator("^", [other, self])
@_overridable_by_reflected("__ror__")
def __or__(self, other): def __or__(self, other):
return Operator("|", [self, other]) return Operator("|", [self, other], src_loc_at=1)
def __ror__(self, other): def __ror__(self, other):
return Operator("|", [other, self]) return Operator("|", [other, self])
@_overridable_by_reflected("__eq__")
def __eq__(self, other): def __eq__(self, other):
return Operator("==", [self, other]) return Operator("==", [self, other], src_loc_at=1)
@_overridable_by_reflected("__ne__")
def __ne__(self, other): def __ne__(self, other):
return Operator("!=", [self, other]) return Operator("!=", [self, other], src_loc_at=1)
@_overridable_by_reflected("__gt__")
def __lt__(self, other): def __lt__(self, other):
return Operator("<", [self, other]) return Operator("<", [self, other], src_loc_at=1)
@_overridable_by_reflected("__ge__")
def __le__(self, other): def __le__(self, other):
return Operator("<=", [self, other]) return Operator("<=", [self, other], src_loc_at=1)
@_overridable_by_reflected("__lt__")
def __gt__(self, other): def __gt__(self, other):
return Operator(">", [self, other]) return Operator(">", [self, other], src_loc_at=1)
@_overridable_by_reflected("__le__")
def __ge__(self, other): def __ge__(self, other):
return Operator(">=", [self, other]) return Operator(">=", [self, other], src_loc_at=1)
def __abs__(self): def __abs__(self):
if self.shape().signed: if self.shape().signed:

2
docs/changes.rst
View file

@ -55,6 +55,7 @@ Implemented RFCs
.. _RFC 19: https://amaranth-lang.org/rfcs/0019-remove-scheduler.html .. _RFC 19: https://amaranth-lang.org/rfcs/0019-remove-scheduler.html
.. _RFC 20: https://amaranth-lang.org/rfcs/0020-deprecate-non-fwft-fifos.html .. _RFC 20: https://amaranth-lang.org/rfcs/0020-deprecate-non-fwft-fifos.html
.. _RFC 22: https://amaranth-lang.org/rfcs/0022-valuecastable-shape.html .. _RFC 22: https://amaranth-lang.org/rfcs/0022-valuecastable-shape.html
.. _RFC 28: https://amaranth-lang.org/rfcs/0028-override-value-operators.html
* `RFC 1`_: Aggregate data structure library * `RFC 1`_: Aggregate data structure library
@ -71,6 +72,7 @@ Implemented RFCs
* `RFC 15`_: Lifting shape-castable objects * `RFC 15`_: Lifting shape-castable objects
* `RFC 20`_: Deprecate non-FWFT FIFOs * `RFC 20`_: Deprecate non-FWFT FIFOs
* `RFC 22`_: Define ``ValueCastable.shape()`` * `RFC 22`_: Define ``ValueCastable.shape()``
* `RFC 28`_: Allow overriding ``Value`` operators
Language changes Language changes

12
tests/test_hdl_rec.py
View file

@ -285,22 +285,22 @@ class RecordTestCase(FHDLTestCase):
# __eq__, __ne__, __lt__, __le__, __gt__, __ge__ # __eq__, __ne__, __lt__, __le__, __gt__, __ge__
self.assertEqual(repr(r1 == 1), "(== (cat (sig r1__a)) (const 1'd1))") self.assertEqual(repr(r1 == 1), "(== (cat (sig r1__a)) (const 1'd1))")
self.assertEqual(repr(r1 == s1), "(== (cat (sig r1__a)) (sig s1))") self.assertEqual(repr(r1 == s1), "(== (cat (sig r1__a)) (sig s1))")
self.assertEqual(repr(s1 == r1), "(== (sig s1) (cat (sig r1__a)))") self.assertEqual(repr(s1 == r1), "(== (cat (sig r1__a)) (sig s1))")
self.assertEqual(repr(r1 != 1), "(!= (cat (sig r1__a)) (const 1'd1))") self.assertEqual(repr(r1 != 1), "(!= (cat (sig r1__a)) (const 1'd1))")
self.assertEqual(repr(r1 != s1), "(!= (cat (sig r1__a)) (sig s1))") self.assertEqual(repr(r1 != s1), "(!= (cat (sig r1__a)) (sig s1))")
self.assertEqual(repr(s1 != r1), "(!= (sig s1) (cat (sig r1__a)))") self.assertEqual(repr(s1 != r1), "(!= (cat (sig r1__a)) (sig s1))")
self.assertEqual(repr(r1 < 1), "(< (cat (sig r1__a)) (const 1'd1))") self.assertEqual(repr(r1 < 1), "(< (cat (sig r1__a)) (const 1'd1))")
self.assertEqual(repr(r1 < s1), "(< (cat (sig r1__a)) (sig s1))") self.assertEqual(repr(r1 < s1), "(< (cat (sig r1__a)) (sig s1))")
self.assertEqual(repr(s1 < r1), "(< (sig s1) (cat (sig r1__a)))") self.assertEqual(repr(s1 < r1), "(> (cat (sig r1__a)) (sig s1))")
self.assertEqual(repr(r1 <= 1), "(<= (cat (sig r1__a)) (const 1'd1))") self.assertEqual(repr(r1 <= 1), "(<= (cat (sig r1__a)) (const 1'd1))")
self.assertEqual(repr(r1 <= s1), "(<= (cat (sig r1__a)) (sig s1))") self.assertEqual(repr(r1 <= s1), "(<= (cat (sig r1__a)) (sig s1))")
self.assertEqual(repr(s1 <= r1), "(<= (sig s1) (cat (sig r1__a)))") self.assertEqual(repr(s1 <= r1), "(>= (cat (sig r1__a)) (sig s1))")
self.assertEqual(repr(r1 > 1), "(> (cat (sig r1__a)) (const 1'd1))") self.assertEqual(repr(r1 > 1), "(> (cat (sig r1__a)) (const 1'd1))")
self.assertEqual(repr(r1 > s1), "(> (cat (sig r1__a)) (sig s1))") self.assertEqual(repr(r1 > s1), "(> (cat (sig r1__a)) (sig s1))")
self.assertEqual(repr(s1 > r1), "(> (sig s1) (cat (sig r1__a)))") self.assertEqual(repr(s1 > r1), "(< (cat (sig r1__a)) (sig s1))")
self.assertEqual(repr(r1 >= 1), "(>= (cat (sig r1__a)) (const 1'd1))") self.assertEqual(repr(r1 >= 1), "(>= (cat (sig r1__a)) (const 1'd1))")
self.assertEqual(repr(r1 >= s1), "(>= (cat (sig r1__a)) (sig s1))") self.assertEqual(repr(r1 >= s1), "(>= (cat (sig r1__a)) (sig s1))")
self.assertEqual(repr(s1 >= r1), "(>= (sig s1) (cat (sig r1__a)))") self.assertEqual(repr(s1 >= r1), "(<= (cat (sig r1__a)) (sig s1))")
# __abs__, __len__ # __abs__, __len__
self.assertEqual(repr(abs(r1)), "(cat (sig r1__a))") self.assertEqual(repr(abs(r1)), "(cat (sig r1__a))")