feat: stuff

pkg/lambda/reducer.go

@@ -10,11 +10,11 @@ import (
 // for lambda calculus expressions.
 type NormalOrderReducer struct {
 	emitter.BaseEmitter[reducer.Event]
-	expression Expression
+	expression *Expression
 }
 
 // NewNormalOrderReducer creates a new normal order reducer.
-func NewNormalOrderReducer(expression Expression) *NormalOrderReducer {
+func NewNormalOrderReducer(expression *Expression) *NormalOrderReducer {
 	return &NormalOrderReducer{
 		BaseEmitter: *emitter.New[reducer.Event](),
 		expression:  expression,
@@ -23,7 +23,7 @@ func NewNormalOrderReducer(expression Expression) *NormalOrderReducer {
 
 // Expression returns the current expression state.
 func (r *NormalOrderReducer) Expression() expr.Expression {
-	return r.expression
+	return *r.expression
 }
 
 func isViable(e *Expression) (*Abstraction, Expression, bool) {
@@ -42,7 +42,7 @@ func isViable(e *Expression) (*Abstraction, Expression, bool) {
 // The expression must be a lambda.Expression; other types are returned unchanged.
 func (r *NormalOrderReducer) Reduce() {
 	r.Emit(reducer.StartEvent)
-	it := NewIterator(&r.expression)
+	it := NewIterator(r.expression)
 
 	for !it.Done() {
 		if fn, arg, ok := isViable(it.Current()); !ok {