py/objcomplex: Add mp_obj_get_complex_maybe for use in complex bin-op.

This allows complex binary operations to fail gracefully with unsupported
operation rather than raising an exception, so that special methods work
correctly.

Signed-off-by: Damien George <damien@micropython.org>

py/obj.c

@@ -371,7 +371,7 @@ mp_float_t mp_obj_get_float(mp_obj_t arg) {
 }
 
 #if MICROPY_PY_BUILTINS_COMPLEX
-void mp_obj_get_complex(mp_obj_t arg, mp_float_t *real, mp_float_t *imag) {
+bool mp_obj_get_complex_maybe(mp_obj_t arg, mp_float_t *real, mp_float_t *imag) {
     if (arg == mp_const_false) {
         *real = 0;
         *imag = 0;
@@ -392,6 +392,13 @@ void mp_obj_get_complex(mp_obj_t arg, mp_float_t *real, mp_float_t *imag) {
     } else if (mp_obj_is_type(arg, &mp_type_complex)) {
         mp_obj_complex_get(arg, real, imag);
     } else {
+        return false;
+    }
+    return true;
+}
+
+void mp_obj_get_complex(mp_obj_t arg, mp_float_t *real, mp_float_t *imag) {
+    if (!mp_obj_get_complex_maybe(arg, real, imag)) {
         #if MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_TERSE
         mp_raise_TypeError(MP_ERROR_TEXT("can't convert to complex"));
         #else

py/obj.h

@@ -778,6 +778,7 @@ bool mp_obj_get_int_maybe(mp_const_obj_t arg, mp_int_t *value);
 mp_float_t mp_obj_get_float(mp_obj_t self_in);
 bool mp_obj_get_float_maybe(mp_obj_t arg, mp_float_t *value);
 void mp_obj_get_complex(mp_obj_t self_in, mp_float_t *real, mp_float_t *imag);
+bool mp_obj_get_complex_maybe(mp_obj_t self_in, mp_float_t *real, mp_float_t *imag);
 #endif
 void mp_obj_get_array(mp_obj_t o, size_t *len, mp_obj_t **items); // *items may point inside a GC block
 void mp_obj_get_array_fixed_n(mp_obj_t o, size_t len, mp_obj_t **items); // *items may point inside a GC block

py/objcomplex.c

@@ -178,7 +178,10 @@ void mp_obj_complex_get(mp_obj_t self_in, mp_float_t *real, mp_float_t *imag) {
 
 mp_obj_t mp_obj_complex_binary_op(mp_binary_op_t op, mp_float_t lhs_real, mp_float_t lhs_imag, mp_obj_t rhs_in) {
     mp_float_t rhs_real, rhs_imag;
-    mp_obj_get_complex(rhs_in, &rhs_real, &rhs_imag); // can be any type, this function will convert to float (if possible)
+    if (!mp_obj_get_complex_maybe(rhs_in, &rhs_real, &rhs_imag)) {
+        return MP_OBJ_NULL; // op not supported
+    }
+
     switch (op) {
         case MP_BINARY_OP_ADD:
         case MP_BINARY_OP_INPLACE_ADD:

tests/float/cmath_fun.py

@@ -57,3 +57,9 @@ for f_name, f, test_vals in functions:
             if abs(real) < 1e-6:
                 real = 0.0
             print("complex(%.5g, %.5g)" % (real, ret.imag))
+
+# test invalid type passed to cmath function
+try:
+    log([])
+except TypeError:
+    print("TypeError")

tests/float/complex_special_mehods.py

@@ -0,0 +1,15 @@
+# test complex interacting with special methods
+
+
+class A:
+    def __add__(self, x):
+        print("__add__")
+        return 1
+
+    def __radd__(self, x):
+        print("__radd__")
+        return 2
+
+
+print(A() + 1j)
+print(1j + A())

tests/run-tests

@@ -355,6 +355,7 @@ def run_tests(pyb, tests, args, base_path="."):
     if not has_complex:
         skip_tests.add('float/complex1.py')
         skip_tests.add('float/complex1_intbig.py')
+        skip_tests.add('float/complex_special_mehods.py')
         skip_tests.add('float/int_big_float.py')
         skip_tests.add('float/true_value.py')
         skip_tests.add('float/types.py')