py/objstr: Return unsupported binop instead of raising TypeError.

So that user types can implement reverse operators and have them work with
str on the left-hand-side, eg `"a" + UserType()`.

Signed-off-by: Damien George <damien@micropython.org>
This commit is contained in:
Damien George 2023-05-12 23:17:20 +10:00
parent ca9068e0ef
commit 4b57330465
2 changed files with 41 additions and 2 deletions

View File

@ -403,7 +403,16 @@ mp_obj_t mp_obj_str_binary_op(mp_binary_op_t op, mp_obj_t lhs_in, mp_obj_t rhs_i
} else {
// LHS is str and RHS has an incompatible type
// (except if operation is EQUAL, but that's handled by mp_obj_equal)
bad_implicit_conversion(rhs_in);
// CONTAINS must fail with a bad-implicit-conversion exception, because
// otherwise mp_binary_op() will fallback to `list(lhs).__contains__(rhs)`.
if (op == MP_BINARY_OP_CONTAINS) {
bad_implicit_conversion(rhs_in);
}
// All other operations are not supported, and may be handled by another
// type, eg for reverse operations.
return MP_OBJ_NULL;
}
switch (op) {

View File

@ -1,5 +1,7 @@
class A:
# Test reverse operators.
# Test user type with integers.
class A:
def __init__(self, v):
self.v = v
@ -14,5 +16,33 @@ class A:
def __repr__(self):
return "A({})".format(self.v)
print(A(3) + 1)
print(2 + A(5))
# Test user type with strings.
class B:
def __init__(self, v):
self.v = v
def __repr__(self):
return "B({})".format(self.v)
def __ror__(self, o):
return B(o + "|" + self.v)
def __radd__(self, o):
return B(o + "+" + self.v)
def __rmul__(self, o):
return B(o + "*" + self.v)
def __rtruediv__(self, o):
return B(o + "/" + self.v)
print("a" | B("b"))
print("a" + B("b"))
print("a" * B("b"))
print("a" / B("b"))