niti: update intern implementation of `io_write`.

Signed-off-by: Jean Privat <jean@pryen.org>

diff --git a/src/interpreter/primitive_types.nit b/src/interpreter/primitive_types.nit
index 8f12c78..9a2e977 100644 (file)
--- a/src/interpreter/primitive_types.nit
+++ b/src/interpreter/primitive_types.nit
@@ -54,9 +54,9 @@ class PrimitiveNativeFile
                return str.length
        end
 
-       fun io_write(buf: NativeString, len: Int): Int do
-               if file isa FileStream then return file.as(FileStream)._file.io_write(buf, len)
-               file.as(Writer).write(buf.to_s_with_length(len))
+       fun io_write(buf: NativeString, from, len: Int): Int do
+               if file isa FileStream then return file.as(FileStream)._file.io_write(buf, from, len)
+               file.as(Writer).write(buf.to_s_with_length(len).substring_from(from))
                return len
        end