diff --git a/ds/array.c b/ds/array.c
index b0119e8..d5e7fe9 100644
--- a/ds/array.c
+++ b/ds/array.c
@@ -323,11 +323,11 @@ static void array_to_string(const fx_object *obj, fx_stream *out)
 	struct fx_array_p *array = fx_object_get_private(obj, FX_TYPE_ARRAY);
 
 	if (!array->ar_len) {
-		fx_stream_write_string(out, "[]", NULL);
+		fx_stream_write_cstr(out, "[]", NULL);
 		return;
 	}
 
-	fx_stream_write_string(out, "[\n", NULL);
+	fx_stream_write_cstr(out, "[\n", NULL);
 
 	fx_stream_push_indent(out, 1);
 	size_t len = array_size(array);
@@ -347,7 +347,7 @@ static void array_to_string(const fx_object *obj, fx_stream *out)
 		}
 
 		if (i < len - 1) {
-			fx_stream_write_string(out, ",", NULL);
+			fx_stream_write_cstr(out, ",", NULL);
 		}
 
 		fx_stream_write_char(out, '\n');
diff --git a/ds/dict.c b/ds/dict.c
index 37d1bed..f9f9af7 100644
--- a/ds/dict.c
+++ b/ds/dict.c
@@ -147,7 +147,7 @@ static fx_object *dict_at(const struct fx_dict_p *dict, const char *key)
 		struct fx_dict_bucket_item *item
 			= fx_unbox(struct fx_dict_bucket_item, entry, bi_entry);
 
-		if (!strcmp(fx_string_ptr(item->bi_str), key)) {
+		if (!strcmp(fx_string_get_cstr(item->bi_str), key)) {
 			return item->bi_value;
 		}
 
@@ -425,11 +425,11 @@ static void dict_to_string(const fx_object *obj, fx_stream *out)
 	struct fx_dict_p *dict = fx_object_get_private(obj, FX_TYPE_DICT);
 
 	if (dict_is_empty(dict)) {
-		fx_stream_write_string(out, "{}", NULL);
+		fx_stream_write_cstr(out, "{}", NULL);
 		return;
 	}
 
-	fx_stream_write_string(out, "{\n", NULL);
+	fx_stream_write_cstr(out, "{\n", NULL);
 
 	fx_stream_push_indent(out, 1);
 	size_t len = dict_get_size(dict);
@@ -446,7 +446,7 @@ static void dict_to_string(const fx_object *obj, fx_stream *out)
 				struct fx_dict_bucket_item, entry, bi_entry);
 
 			fx_object_to_string(item->bi_str, out);
-			fx_stream_write_string(out, ": ", NULL);
+			fx_stream_write_cstr(out, ": ", NULL);
 
 			bool is_string = fx_object_is_type(
 				item->bi_value, FX_TYPE_STRING);
@@ -462,7 +462,7 @@ static void dict_to_string(const fx_object *obj, fx_stream *out)
 			}
 
 			if (i < len - 1) {
-				fx_stream_write_string(out, ",", NULL);
+				fx_stream_write_cstr(out, ",", NULL);
 			}
 
 			fx_stream_write_char(out, '\n');
diff --git a/ds/include/fx/ds/string.h b/ds/include/fx/ds/string.h
index e024a98..6ca2ef7 100644
--- a/ds/include/fx/ds/string.h
+++ b/ds/include/fx/ds/string.h
@@ -52,18 +52,22 @@ FX_API fx_string *fx_string_duplicate(const fx_string *str);
 FX_API char *fx_string_steal(fx_string *str);
 FX_API fx_status fx_string_reserve(fx_string *str, size_t capacity);
 FX_API fx_status fx_string_replace(
-	fx_string *str, size_t start, size_t length, const char *new_data);
+	fx_string *str,
+	size_t start,
+	size_t length,
+	const char *new_data);
 FX_API fx_status fx_string_replace_all(fx_string *str, const char *new_data);
 FX_API fx_status fx_string_replace_all_with_stringstream(
-	fx_string *str, const fx_stringstream *new_data);
+	fx_string *str,
+	const fx_stringstream *new_data);
 FX_API fx_status fx_string_remove(fx_string *str, size_t start, size_t length);
 FX_API fx_status fx_string_transform(fx_string *str, int (*transformer)(int));
 FX_API fx_status fx_string_trim(fx_string *str);
-static inline fx_status fx_string_toupper(fx_string *str)
+static inline fx_status fx_string_transform_uppercase(fx_string *str)
 {
 	return fx_string_transform(str, toupper);
 }
-static inline fx_status fx_string_tolower(fx_string *str)
+static inline fx_status fx_string_transform_lowercase(fx_string *str)
 {
 	return fx_string_transform(str, tolower);
 }
diff --git a/ds/number.c b/ds/number.c
index d3f9172..26012a0 100644
--- a/ds/number.c
+++ b/ds/number.c
@@ -532,110 +532,188 @@ static void print_inf(const struct fx_number_p *n, fx_stream *out)
 {
 	switch (n->n_type) {
 	case FX_NUMBER_INT8:
-		fx_stream_write_string(out, n->n_value.v_int8 < 0 ? "-" : "", NULL);
+		fx_stream_write_cstr(
+			out,
+			n->n_value.v_int8 < 0 ? "-" : "",
+			NULL);
 		break;
 	case FX_NUMBER_INT16:
-		fx_stream_write_string(out, n->n_value.v_int16 < 0 ? "-" : "", NULL);
+		fx_stream_write_cstr(
+			out,
+			n->n_value.v_int16 < 0 ? "-" : "",
+			NULL);
 		break;
 	case FX_NUMBER_INT32:
-		fx_stream_write_string(out, n->n_value.v_int32 < 0 ? "-" : "", NULL);
+		fx_stream_write_cstr(
+			out,
+			n->n_value.v_int32 < 0 ? "-" : "",
+			NULL);
 		break;
 	case FX_NUMBER_INT64:
-		fx_stream_write_string(out, n->n_value.v_int64 < 0 ? "-" : "", NULL);
+		fx_stream_write_cstr(
+			out,
+			n->n_value.v_int64 < 0 ? "-" : "",
+			NULL);
 		break;
 	case FX_NUMBER_FLOAT32:
-		fx_stream_write_string(
-			out, n->n_value.v_float32 < 0 ? "-" : "", NULL);
+		fx_stream_write_cstr(
+			out,
+			n->n_value.v_float32 < 0 ? "-" : "",
+			NULL);
 		break;
 	case FX_NUMBER_FLOAT64:
-		fx_stream_write_string(
-			out, n->n_value.v_float64 < 0 ? "-" : "", NULL);
+		fx_stream_write_cstr(
+			out,
+			n->n_value.v_float64 < 0 ? "-" : "",
+			NULL);
 		break;
 	case FX_NUMBER_CHAR:
-		fx_stream_write_string(out, n->n_value.v_char < 0 ? "-" : "", NULL);
+		fx_stream_write_cstr(
+			out,
+			n->n_value.v_char < 0 ? "-" : "",
+			NULL);
 		break;
 	case FX_NUMBER_SHORT:
-		fx_stream_write_string(out, n->n_value.v_short < 0 ? "-" : "", NULL);
+		fx_stream_write_cstr(
+			out,
+			n->n_value.v_short < 0 ? "-" : "",
+			NULL);
 		break;
 	case FX_NUMBER_INT:
-		fx_stream_write_string(out, n->n_value.v_int < 0 ? "-" : "", NULL);
+		fx_stream_write_cstr(
+			out,
+			n->n_value.v_int < 0 ? "-" : "",
+			NULL);
 		break;
 	case FX_NUMBER_LONG:
-		fx_stream_write_string(out, n->n_value.v_long < 0 ? "-" : "", NULL);
+		fx_stream_write_cstr(
+			out,
+			n->n_value.v_long < 0 ? "-" : "",
+			NULL);
 		break;
 	case FX_NUMBER_LONGLONG:
-		fx_stream_write_string(
-			out, n->n_value.v_longlong < 0 ? "-" : "", NULL);
+		fx_stream_write_cstr(
+			out,
+			n->n_value.v_longlong < 0 ? "-" : "",
+			NULL);
 		break;
 	case FX_NUMBER_FLOAT:
-		fx_stream_write_string(out, n->n_value.v_float < 0 ? "-" : "", NULL);
+		fx_stream_write_cstr(
+			out,
+			n->n_value.v_float < 0 ? "-" : "",
+			NULL);
 		break;
 	case FX_NUMBER_DOUBLE:
-		fx_stream_write_string(out, n->n_value.v_double < 0 ? "-" : "", NULL);
+		fx_stream_write_cstr(
+			out,
+			n->n_value.v_double < 0 ? "-" : "",
+			NULL);
 		break;
 	case FX_NUMBER_SIZE_T:
-		fx_stream_write_string(out, n->n_value.v_size_t < 0 ? "-" : "", NULL);
+		fx_stream_write_cstr(
+			out,
+			n->n_value.v_size_t < 0 ? "-" : "",
+			NULL);
 		break;
 	default:
 		break;
 	}
 
-	fx_stream_write_string(out, "INF", NULL);
+	fx_stream_write_cstr(out, "INF", NULL);
 }
 
 static void print_nan(const struct fx_number_p *n, fx_stream *out)
 {
 	switch (n->n_type) {
 	case FX_NUMBER_INT8:
-		fx_stream_write_string(out, n->n_value.v_int8 < 0 ? "-" : "", NULL);
+		fx_stream_write_cstr(
+			out,
+			n->n_value.v_int8 < 0 ? "-" : "",
+			NULL);
 		break;
 	case FX_NUMBER_INT16:
-		fx_stream_write_string(out, n->n_value.v_int16 < 0 ? "-" : "", NULL);
+		fx_stream_write_cstr(
+			out,
+			n->n_value.v_int16 < 0 ? "-" : "",
+			NULL);
 		break;
 	case FX_NUMBER_INT32:
-		fx_stream_write_string(out, n->n_value.v_int32 < 0 ? "-" : "", NULL);
+		fx_stream_write_cstr(
+			out,
+			n->n_value.v_int32 < 0 ? "-" : "",
+			NULL);
 		break;
 	case FX_NUMBER_INT64:
-		fx_stream_write_string(out, n->n_value.v_int64 < 0 ? "-" : "", NULL);
+		fx_stream_write_cstr(
+			out,
+			n->n_value.v_int64 < 0 ? "-" : "",
+			NULL);
 		break;
 	case FX_NUMBER_FLOAT32:
-		fx_stream_write_string(
-			out, n->n_value.v_float32 < 0 ? "-" : "", NULL);
+		fx_stream_write_cstr(
+			out,
+			n->n_value.v_float32 < 0 ? "-" : "",
+			NULL);
 		break;
 	case FX_NUMBER_FLOAT64:
-		fx_stream_write_string(
-			out, n->n_value.v_float64 < 0 ? "-" : "", NULL);
+		fx_stream_write_cstr(
+			out,
+			n->n_value.v_float64 < 0 ? "-" : "",
+			NULL);
 		break;
 	case FX_NUMBER_CHAR:
-		fx_stream_write_string(out, n->n_value.v_char < 0 ? "-" : "", NULL);
+		fx_stream_write_cstr(
+			out,
+			n->n_value.v_char < 0 ? "-" : "",
+			NULL);
 		break;
 	case FX_NUMBER_SHORT:
-		fx_stream_write_string(out, n->n_value.v_short < 0 ? "-" : "", NULL);
+		fx_stream_write_cstr(
+			out,
+			n->n_value.v_short < 0 ? "-" : "",
+			NULL);
 		break;
 	case FX_NUMBER_INT:
-		fx_stream_write_string(out, n->n_value.v_int < 0 ? "-" : "", NULL);
+		fx_stream_write_cstr(
+			out,
+			n->n_value.v_int < 0 ? "-" : "",
+			NULL);
 		break;
 	case FX_NUMBER_LONG:
-		fx_stream_write_string(out, n->n_value.v_long < 0 ? "-" : "", NULL);
+		fx_stream_write_cstr(
+			out,
+			n->n_value.v_long < 0 ? "-" : "",
+			NULL);
 		break;
 	case FX_NUMBER_LONGLONG:
-		fx_stream_write_string(
-			out, n->n_value.v_longlong < 0 ? "-" : "", NULL);
+		fx_stream_write_cstr(
+			out,
+			n->n_value.v_longlong < 0 ? "-" : "",
+			NULL);
 		break;
 	case FX_NUMBER_FLOAT:
-		fx_stream_write_string(out, n->n_value.v_float < 0 ? "-" : "", NULL);
+		fx_stream_write_cstr(
+			out,
+			n->n_value.v_float < 0 ? "-" : "",
+			NULL);
 		break;
 	case FX_NUMBER_DOUBLE:
-		fx_stream_write_string(out, n->n_value.v_double < 0 ? "-" : "", NULL);
+		fx_stream_write_cstr(
+			out,
+			n->n_value.v_double < 0 ? "-" : "",
+			NULL);
 		break;
 	case FX_NUMBER_SIZE_T:
-		fx_stream_write_string(out, n->n_value.v_size_t < 0 ? "-" : "", NULL);
+		fx_stream_write_cstr(
+			out,
+			n->n_value.v_size_t < 0 ? "-" : "",
+			NULL);
 		break;
 	default:
 		break;
 	}
 
-	fx_stream_write_string(out, "NaN", NULL);
+	fx_stream_write_cstr(out, "NaN", NULL);
 }
 
 /*** PUBLIC FUNCTIONS *********************************************************/
diff --git a/ds/string.c b/ds/string.c
index d29c190..f856d48 100644
--- a/ds/string.c
+++ b/ds/string.c
@@ -1297,7 +1297,7 @@ void fx_string_pop_back(fx_string *str)
 	FX_CLASS_DISPATCH_STATIC_0(FX_TYPE_STRING, string_pop_back, str);
 }
 
-const char *fx_string_ptr(const fx_string *str)
+const char *fx_string_get_cstr(const fx_string *str)
 {
 	FX_CLASS_DISPATCH_STATIC_0(FX_TYPE_STRING, string_ptr, str);
 }
diff --git a/ds/uuid.c b/ds/uuid.c
index 4be30f8..1069c0b 100644
--- a/ds/uuid.c
+++ b/ds/uuid.c
@@ -188,7 +188,7 @@ fx_uuid *fx_uuid_create_from_uuid_bytes(const union fx_uuid_bytes *bytes)
 
 fx_uuid *fx_uuid_create_from_string(const fx_string *string)
 {
-	return fx_uuid_create_from_cstr(fx_string_ptr(string));
+	return fx_uuid_create_from_cstr(fx_string_get_cstr(string));
 }
 
 /*** VIRTUAL FUNCTIONS ********************************************************/
@@ -207,7 +207,7 @@ static void uuid_to_string(const fx_object *uuid, fx_stream *out)
 {
 	char str[FX_UUID_STRING_MAX];
 	fx_uuid_to_cstr(uuid, str);
-	fx_stream_write_string(out, str, NULL);
+	fx_stream_write_cstr(out, str, NULL);
 }
 
 /*** CLASS DEFINITION *********************************************************/