From 57781b5e3b44192b1d4684c1665c986ca9b2d138 Mon Sep 17 00:00:00 2001
From: Leon Mika <lmika@lmika.org>
Date: Tue, 30 Apr 2024 21:55:18 +1000
Subject: [PATCH] Added ErrHalt

---
 ucl/inst.go | 3 +++
 ucl/objs.go | 2 ++
 2 files changed, 5 insertions(+)

diff --git a/ucl/inst.go b/ucl/inst.go
index 7493338..65f0c90 100644
--- a/ucl/inst.go
+++ b/ucl/inst.go
@@ -73,6 +73,9 @@ func (inst *Inst) Out() io.Writer {
 func (inst *Inst) Eval(ctx context.Context, expr string) (any, error) {
 	res, err := inst.eval(ctx, expr)
 	if err != nil {
+		if errors.Is(err, ErrHalt) {
+			return nil, nil
+		}
 		return nil, err
 	}
 
diff --git a/ucl/objs.go b/ucl/objs.go
index 47bd7cb..bfa3081 100644
--- a/ucl/objs.go
+++ b/ucl/objs.go
@@ -465,3 +465,5 @@ type errReturn struct {
 func (e errReturn) Error() string {
 	return "return"
 }
+
+var ErrHalt = errors.New("halt")