X-Git-Url: http://nitlanguage.org

diff --git a/src/interpreter/naive_interpreter.nit b/src/interpreter/naive_interpreter.nit
index aba779a..1232a65 100644
--- a/src/interpreter/naive_interpreter.nit
+++ b/src/interpreter/naive_interpreter.nit
@@ -1001,11 +1001,11 @@ redef class AMethPropdef
 			else if pname == "file_exists" then
 				return v.bool_instance(recvval.to_s.file_exists)
 			else if pname == "file_mkdir" then
-				recvval.to_s.mkdir
-				return null
+				var res = recvval.to_s.mkdir
+				return v.bool_instance(res == null)
 			else if pname == "file_chdir" then
-				recvval.to_s.chdir
-				return null
+				var res = recvval.to_s.chdir
+				return v.bool_instance(res == null)
 			else if pname == "file_realpath" then
 				return v.native_string_instance(recvval.to_s.realpath)
 			else if pname == "get_environ" then
@@ -1016,6 +1016,9 @@ redef class AMethPropdef
 				return v.int_instance(res)
 			else if pname == "atof" then
 				return v.float_instance(recvval.to_f)
+			else if pname == "fast_cstring" then
+				var ns = recvval.to_cstring.to_s.substring_from(args[1].to_i)
+				return v.native_string_instance(ns)
 			end
 		else if cname == "String" then
 			var cs = v.send(v.force_get_primitive_method("to_cstring", args.first.mtype), [args.first])