Improves RunTransducer by reusing state slices for states and newStates

1 files changed, 4 insertions, 1 deletions

diff --git a/subex/main.go b/subex/main.go
index 638e0f5..ebd87cb 100644
--- a/subex/main.go
+++ b/subex/main.go
@@ -131,12 +131,15 @@ func RunTransducer(transducer Transducer, input []walk.Atom) (output []walk.Atom
 		},
 		store: make([][]walk.Atom, transducer.storeSize),
 	}}
+	var tmp []SubexBranch
+	newStates := make([]SubexBranch, 0, 2)
 	for _, piece := range input {
-		var newStates []SubexBranch
 		for _, state := range states {
 			newStates = append(newStates, state.eat(piece)...)
 		}
+		tmp = states
 		states = pruneStates(newStates)
+		newStates = tmp[:0]
 		if len(states) == 0 {
 			return nil, true
 		}