Move same magic methods from Expr and GenExpr to ExprLike (#1204)

* Consolidate operator overloads into ExprLike

Move common operator dunder methods (__neg__, __radd__, __sub__, __rsub__, __rmul__, __richcmp__) into the base ExprLike class and remove their duplicate implementations from Expr and GenExpr. This consolidates operator behavior across expression types, forwarding rich comparisons to _expr_richcmp and reducing code duplication for negation, arithmetic and reflected operations.

* Consolidate ExprLike operator methods

Move and centralize operator overloads for ExprLike: __radd__, __sub__, __rsub__, __rmul__, __neg__ and __richcmp__ are added earlier in the class and the duplicate implementations later in the file were removed. This refactor cleans up the class definition and avoids duplicated method definitions.

* Move __rtruediv__ to ExprLike base class

Consolidate reflected true-division handling by adding __rtruediv__ to the ExprLike base class and removing duplicate implementations from Expr and GenExpr. The reflected division now uniformly uses buildGenExprObj(other) / self, reducing code duplication and ensuring consistent behavior across expression types.

* Update changelog: move magic methods to ExprLike

Document a refactor that moves several dunder methods (__radd__, __sub__, __rsub__, __rmul__, __richcmp__, __neg__, __rtruediv__) into the ExprLike base class to centralize operator behavior. This change only updates CHANGELOG.md to record the API/internal restructuring.

* Update CHANGELOG.md

* Mark reflected dunder methods positional-only

Add the positional-only marker ('/') to several operator method signatures in ExprLike to prevent passing the operand as a keyword and to align with CPython semantics. Affected methods: __radd__, __sub__, __rsub__, __rmul__, and __rtruediv__. This is a signature-level change only and should not alter runtime behavior.

* Consolidate arithmetic dunders into ExprLike

Update src/pyscipopt/scip.pyi: add missing arithmetic/operator dunder declarations (__radd__, __sub__, __rsub__, __rmul__, __rtruediv__, __neg__) to the ExprLike base stub and remove redundant/operator declarations from Expr and GenExpr. This consolidates common operator signatures in the base protocol, reduces duplication, and improves typing/stub consistency.

* Update CHANGELOG.md

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* style: format scip.pyi with ruff

Delete an extraneous blank line between the end of ExprLike and the @disjoint_base decorator/Expr class in src/pyscipopt/scip.pyi to tidy file formatting. No functional changes.

* Refine operator type hints in scip.pyi

Replace Incomplete with object for several ExprLike operator stubs (__radd__, __sub__, __rsub__, __rmul__, __rtruediv__, __neg__) to relax/standardize return and operand typing. Also add missing __rtruediv__ stubs to Expr and GenExpr. These changes improve the type stubs for static type checkers and better reflect Python operator semantics.

* Update CHANGELOG.md

* Make ExprLike.__neg__ positional-only

Add the positional-only marker (/) to the ExprLike.__neg__ signature in src/pyscipopt/expr.pxi. This enforces that the unary negation method cannot be called with keyword arguments and aligns the signature with Python/Cython expectations, avoiding potential warnings or misuse.

* Refine ExprLike operator return types

Update type stubs in src/pyscipopt/scip.pyi to change return types of several ExprLike dunder operators from object to Incomplete for improved typing precision. Affected methods: __radd__, __sub__, __rsub__, __rmul__, __rtruediv__, and __neg__. This is a type-only change with no runtime behavior modifications.

* Annotate __rtruediv__ return type as GenExpr

Add explicit GenExpr return annotations for __rtruediv__ across implementation and typing stub. Updated src/pyscipopt/expr.pxi to annotate ExprLike, Expr and GenExpr __rtruediv__ methods with -> GenExpr, and updated src/pyscipopt/scip.pyi to change the stub return types from object to GenExpr for Expr.__rtruediv__ and GenExpr.__rtruediv__. This improves static typing consistency between the Cython implementation and the Python stubs.

* Annotate __neg__ return type

Update negation operator type hints to return Union[Expr, GenExpr].

- src/pyscipopt/expr.pxi: add a Cython return annotation for __neg__.
- src/pyscipopt/scip.pyi: change __neg__ from Incomplete to Union[Expr, GenExpr].

These changes improve static typing and IDE support by accurately describing the result of unary negation on expression-like objects.

* Unify __rtruediv__ typing in stubs

Update typing in src/pyscipopt/scip.pyi: change ExprLike.__rtruediv__ return type from Incomplete to GenExpr and remove duplicate __rtruediv__ declarations from Expr and GenExpr. This consolidates the right-division signature in the base ExprLike class to avoid conflicting or redundant stub definitions and improve type consistency.

* Mark __neg__ as positional-only in scip.pyi

Update the typing stub for ExprLike.__neg__ in src/pyscipopt/scip.pyi to include the positional-only marker (/). This clarifies that __neg__ accepts no keyword arguments and returns Union[Expr, GenExpr]; no runtime behavior changes.

* Resolve CHANGELOG merge conflict

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Co-authored-by: João Dionísio <57299939+Joao-Dionisio@users.noreply.github.com>
Co-authored-by: Joao-Dionisio <joao.goncalves.dionisio@gmail.com>

Author: 3 people

CHANGELOG.md

@@ -5,6 +5,7 @@
 - Added `addConsCumulative()` for SCIP cumulative constraints (#1222)
 ### Fixed
 ### Changed
+- Move magic methods (`__radd__`, `__sub__`, `__rsub__`, `__rmul__`, `__richcmp__`, `__neg__`, and `__rtruediv__`) to `ExprLike` base class (#1204)
 - Speed up `Expr.__add__` and `Expr.__iadd__` via the C-level API
 ### Removed
 

src/pyscipopt/expr.pxi

@@ -257,6 +257,27 @@ cdef class ExprLike:
 
         return NotImplemented
 
+    def __radd__(self, other, /):
+        return self + other
+
+    def __sub__(self, other, /):
+        return self + (-other)
+
+    def __rsub__(self, other, /):
+        return (-self) + other
+
+    def __rmul__(self, other, /):
+        return self * other
+
+    def __rtruediv__(self, other, /) -> GenExpr:
+        return buildGenExprObj(other) / self
+
+    def __richcmp__(self, other, int op):
+        return _expr_richcmp(self, other, op)
+
+    def __neg__(self, /) -> Union[Expr, GenExpr]:
+        return self * -1.0
+
     def __abs__(self) -> GenExpr:
         return UnaryExpr(Operator.fabs, buildGenExprObj(self))
 
@@ -358,11 +379,10 @@ cdef class Expr(ExprLike):
             return 1.0 / other * self
         return buildGenExprObj(self) / other
 
-    def __rtruediv__(self, other):
-        ''' other / self '''
+    def __rtruediv__(self, other, /) -> GenExpr:
         if not _is_expr_compatible(other):
             return NotImplemented
-        return buildGenExprObj(other) / self
+        return super().__rtruediv__(other)
 
     def __pow__(self, other, modulo):
         if float(other).is_integer() and other >= 0:
@@ -387,25 +407,6 @@ cdef class Expr(ExprLike):
             raise ValueError("Base of a**x must be positive, as expression is reformulated to scip.exp(x * scip.log(a)); got %g" % base)
         return (self * Constant(base).log()).exp()
 
-    def __neg__(self):
-        return Expr({v:-c for v,c in self.terms.items()})
-
-    def __sub__(self, other):
-        return self + (-other)
-
-    def __radd__(self, other):
-        return self.__add__(other)
-
-    def __rmul__(self, other):
-        return self.__mul__(other)
-
-    def __rsub__(self, other):
-        return -1.0 * self + other
-
-    def __richcmp__(self, other, int op):
-        '''turn it into a constraint'''
-        return _expr_richcmp(self, other, op)
-
     def normalize(self):
         '''remove terms with coefficient of 0'''
         self.terms =  {t:c for (t,c) in self.terms.items() if c != 0.0}
@@ -464,7 +465,6 @@ cdef class ExprCons:
         if not self._rhs is None:
             self._rhs -= c
 
-
     def __richcmp__(self, other, op):
         '''turn it into a constraint'''
         if not _is_number(other):
@@ -690,30 +690,10 @@ cdef class GenExpr(ExprLike):
             raise ZeroDivisionError("cannot divide by 0")
         return self * divisor**(-1)
 
-    def __rtruediv__(self, other):
-        ''' other / self '''
+    def __rtruediv__(self, other, /) -> GenExpr:
         if not _is_genexpr_compatible(other):
             return NotImplemented
-        return buildGenExprObj(other) / self
-
-    def __neg__(self):
-        return -1.0 * self
-
-    def __sub__(self, other):
-        return self + (-other)
-
-    def __radd__(self, other):
-        return self.__add__(other)
-
-    def __rmul__(self, other):
-        return self.__mul__(other)
-
-    def __rsub__(self, other):
-        return -1.0 * self + other
-
-    def __richcmp__(self, other, int op):
-        '''turn it into a constraint'''
-        return _expr_richcmp(self, other, op)
+        return super().__rtruediv__(other)
 
     def degree(self):
         '''Note: none of these expressions should be polynomial'''

src/pyscipopt/scip.pyi

@@ -332,6 +332,12 @@ class ExprLike:
         *args: Incomplete,
         **kwargs: Incomplete,
     ) -> Incomplete: ...
+    def __radd__(self, other: object, /) -> Incomplete: ...
+    def __sub__(self, other: object, /) -> Incomplete: ...
+    def __rsub__(self, other: object, /) -> Incomplete: ...
+    def __rmul__(self, other: object, /) -> Incomplete: ...
+    def __rtruediv__(self, other: object, /) -> GenExpr: ...
+    def __neg__(self, /) -> Union[Expr, GenExpr]: ...
     def __abs__(self) -> GenExpr: ...
     def exp(self) -> GenExpr: ...
     def log(self) -> GenExpr: ...
@@ -345,7 +351,6 @@ class Expr(ExprLike):
     def __init__(self, terms: Incomplete = ...) -> None: ...
     def degree(self) -> Incomplete: ...
     def normalize(self) -> Incomplete: ...
-    def __abs__(self) -> GenExpr: ...
     def __add__(self, other: Incomplete, /) -> Incomplete: ...
     def __eq__(self, other: object, /) -> bool: ...
     def __ge__(self, other: object, /) -> bool: ...
@@ -357,14 +362,8 @@ class Expr(ExprLike):
     def __lt__(self, other: object, /) -> bool: ...
     def __mul__(self, other: Incomplete, /) -> Incomplete: ...
     def __ne__(self, other: object, /) -> bool: ...
-    def __neg__(self) -> Incomplete: ...
     def __pow__(self, other: Incomplete, modulo: Incomplete = ..., /) -> Incomplete: ...
-    def __radd__(self, other: Incomplete, /) -> Incomplete: ...
-    def __rmul__(self, other: Incomplete, /) -> Incomplete: ...
     def __rpow__(self, other: Incomplete, /) -> Incomplete: ...
-    def __rsub__(self, other: Incomplete, /) -> Incomplete: ...
-    def __rtruediv__(self, other: Incomplete, /) -> Incomplete: ...
-    def __sub__(self, other: Incomplete, /) -> Incomplete: ...
     def __truediv__(self, other: Incomplete, /) -> Incomplete: ...
 
 @disjoint_base
@@ -391,7 +390,6 @@ class GenExpr(ExprLike):
     def __init__(self) -> None: ...
     def degree(self) -> Incomplete: ...
     def getOp(self) -> Incomplete: ...
-    def __abs__(self) -> GenExpr: ...
     def __add__(self, other: Incomplete, /) -> Incomplete: ...
     def __eq__(self, other: object, /) -> bool: ...
     def __ge__(self, other: object, /) -> bool: ...
@@ -400,14 +398,8 @@ class GenExpr(ExprLike):
     def __lt__(self, other: object, /) -> bool: ...
     def __mul__(self, other: Incomplete, /) -> Incomplete: ...
     def __ne__(self, other: object, /) -> bool: ...
-    def __neg__(self) -> Incomplete: ...
     def __pow__(self, other: Incomplete, modulo: Incomplete = ..., /) -> Incomplete: ...
-    def __radd__(self, other: Incomplete, /) -> Incomplete: ...
-    def __rmul__(self, other: Incomplete, /) -> Incomplete: ...
     def __rpow__(self, other: Incomplete, /) -> Incomplete: ...
-    def __rsub__(self, other: Incomplete, /) -> Incomplete: ...
-    def __rtruediv__(self, other: Incomplete, /) -> Incomplete: ...
-    def __sub__(self, other: Incomplete, /) -> Incomplete: ...
     def __truediv__(self, other: Incomplete, /) -> Incomplete: ...
 
 @disjoint_base