Add support for binary operations running on preserved operations

Author: saulshanabrook

python/egglog/runtime.py

@@ -793,14 +793,34 @@ def _numeric_binary_method(
         Tries to find the minimum cost conversion of either the LHS or the RHS, by finding all methods with either
         the LHS or the RHS as exactly the right type and then upcasting the other to that type.
         """
+        from .conversion import (  # noqa: PLC0415
+            ConvertError,
+            convert_to_same_type,
+            min_binary_conversion,
+            resolve_type,
+        )
+
+        # 1. switch if reversed method
+        if r_method:
+            self, other = other, self
         # First check if we have a preserved method for this:
         if isinstance(self, RuntimeExpr) and (
-            (preserved_method := self.__egg_class_decl__.preserved_methods.get(method_name)) is not None
+            (preserved_method := self.__egg_class_decl__.preserved_methods.get(name)) is not None
         ):
             return preserved_method.__get__(self)(other)
-        # 1. switch if reversed method
-        if r_method:
-            self, other = other, self
+        # Then check if the self is a Python type and the other side has a preserved method
+        if (
+            not isinstance(self, RuntimeExpr)
+            and isinstance(other, RuntimeExpr)
+            and ((preserved_method := other.__egg_class_decl__.preserved_methods.get(name)) is not None)
+        ):
+            try:
+                new_self = convert_to_same_type(self, other)
+            except ConvertError:
+                pass
+            else:
+                return preserved_method.__get__(new_self)(other)
+
         # If the types don't exactly match to start, then we need to try converting one of them, by finding the cheapest conversion
         if not (
             isinstance(self, RuntimeExpr)
@@ -811,8 +831,6 @@ def _numeric_binary_method(
                 )
             )
         ):
-            from .conversion import min_binary_conversion, resolve_type  # noqa: PLC0415
-
             best_method = min_binary_conversion(name, resolve_type(self), resolve_type(other))
 
             if not best_method:

python/tests/test_high_level.py

@@ -1552,3 +1552,19 @@ def __radd__(self, other: XLike) -> X: ...
 
     assert X(1) + 2 == X(1) + X(2)
     assert 2 + X(1) == X(2) + X(1)
+
+
+def test_binary_preserved():
+    class X(Expr):
+        def __init__(self, value: i64Like) -> None: ...
+
+        @method(preserve=True)
+        def __add__(self, other: T) -> tuple[X, T]:
+            return (self, other)
+
+        def __radd__(self, other: object) -> tuple[X, X]: ...
+
+    converter(i64, X, X)
+
+    assert X(1) + 10 == (X(1), 10)
+    assert 10 + X(1) == (X(10), X(1))