Add :xyz: replacement syntax that removes whatever is before it and inserts whatever is inside it

1 files changed, 13 insertions, 0 deletions

diff --git a/subex/subexstate.go b/subex/subexstate.go
index 997e6ce..b5e1e9b 100644
--- a/subex/subexstate.go
+++ b/subex/subexstate.go
@@ -36,6 +36,19 @@ func (state SubexCaptureBeginState) accepting(store Store, outputStack OutputSta
 	return state.next.accepting(store, outputStack.push(nil))
 }
 
+// Discard the top of the OutputStack
+type SubexDiscardState struct {
+	next SubexState
+}
+func (state SubexDiscardState) eat(store Store, outputStack OutputStack, char walk.Atom) []SubexBranch {
+	_, newStack := outputStack.pop()
+	return state.next.eat(store, newStack, char)
+}
+func (state SubexDiscardState) accepting(store Store, outputStack OutputStack) []OutputStack {
+	_, newStack := outputStack.pop()
+	return state.next.accepting(store, newStack)
+}
+
 // Pop the top of the OutputStack which contains the stuff outputted since the start of the store
 // This outputted data gets stored in a slot
 type SubexStoreEndState struct {