word completion in the C runtime. The runtime/python/test.py example is now using readline with word completion

src/runtime/c/pgf/parser.h

@@ -66,6 +66,10 @@ pgf_parser_next_state(PgfParseState* prev, PgfToken tok);
  * the pool used to create \parse.
  */
 
+GuEnum*
+pgf_parser_completions(PgfParseState* prev, GuString prefix, 
+                       GuPool* pool);
+
 void
 pgf_parser_set_beam_size(PgfParseState* state, double beam_size);