optimizations up to section 5.7.

src/prolog/io.rs

@@ -92,6 +92,8 @@ impl fmt::Display for ControlInstruction {
                 write!(f, "call {}/{}", name, arity),
             &ControlInstruction::Deallocate =>
                 write!(f, "deallocate"),
+            &ControlInstruction::Execute(ref name, arity) =>
+                write!(f, "execute {}/{}", name, arity),
             &ControlInstruction::Proceed =>
                 write!(f, "proceed")
         }
@@ -233,7 +235,7 @@ Each predicate must have the same name and arity.";
             EvalResult::EntrySuccess
         },
         &Ok(TopLevel::Query(ref query)) => {
-            let compiled_query = cg.compile_query(&query);            
+            let compiled_query = cg.compile_query(&query);
             wam.run_query(compiled_query, &cg)
         },
         &Err(_) => {