fix #468

src/bindings/py_str.c

@@ -477,12 +477,14 @@ static bool str_rjust(int argc, py_Ref argv) { return str__widthjust_impl(false,
 
 static bool str_find(int argc, py_Ref argv) {
     if(argc > 3) return TypeError("find() takes at most 3 arguments");
+    c11_string* self = pk_tostr(&argv[0]);
     int start = 0;
     if(argc == 3) {
         PY_CHECK_ARG_TYPE(2, tp_int);
         start = py_toint(py_arg(2));
+        if(start < 0) start += c11_sv__u8_length(c11_string__sv(self));
+        if(start < 0) start = 0;
     }
-    c11_string* self = pk_tostr(&argv[0]);
     PY_CHECK_ARG_TYPE(1, tp_str);
     c11_string* sub = pk_tostr(&argv[1]);
     int res = c11_sv__index2(c11_string__sv(self), c11_string__sv(sub), start);

src/public/PyList.c

@@ -317,6 +317,8 @@ static bool list_index(int argc, py_Ref argv) {
     if(argc == 3) {
         PY_CHECK_ARG_TYPE(2, tp_int);
         start = py_toint(py_arg(2));
+        if(start < 0) start += py_list_len(py_arg(0));
+        if(start < 0) start = 0;
     }
     for(int i = start; i < py_list_len(py_arg(0)); i++) {
         int res = py_equal(py_list_getitem(py_arg(0), i), py_arg(1));

tests/041_str.py

@@ -169,6 +169,7 @@ assert a.index('23') == 1
 
 assert a.index('2', 1) == 1
 assert a.index('1', 0) == 0
+assert a.index('2', -2) == 1
 
 assert a.find('1') == 0
 assert a.find('1', 1) == -1

tests/050_list.py

@@ -75,6 +75,7 @@ assert a.index(3) == 2
 
 assert a.index(2, 1) == 1
 assert a.index(1, 0) == 0
+assert a.index(2, -2) == 1
 
 a, b = [1, 2]
 assert a == 1 and b == 2