From ed981690f82cfad3d2a94654956bed5b705161d1 Mon Sep 17 00:00:00 2001
From: Branden J Brown <zephyrtronium@gmail.com>
Date: Sat, 31 Aug 2024 01:49:47 -0400
Subject: [PATCH] brain: fix panic on @ at end of message

---
 brain/words.go      | 3 +++
 brain/words_test.go | 5 +++++
 2 files changed, 8 insertions(+)

diff --git a/brain/words.go b/brain/words.go
index 0885819..c60efc5 100644
--- a/brain/words.go
+++ b/brain/words.go
@@ -33,6 +33,9 @@ func Tokens(dst []string, msg string) []string {
 			// write for a case that will be uncommon.
 			// In terms of control flow, we can fall through to the next case,
 			// after we skip past the @ itself.
+			if l == len(msg) {
+				break
+			}
 			l++
 			fallthrough
 		case unicode.Is(ln, c):
diff --git a/brain/words_test.go b/brain/words_test.go
index cbb5608..e1936f7 100644
--- a/brain/words_test.go
+++ b/brain/words_test.go
@@ -53,6 +53,11 @@ func TestWords(t *testing.T) {
 			msg:  "@bocchi ryo",
 			want: s("@bocchi ", "ryo "),
 		},
+		{
+			name: "at-end",
+			msg:  "bocchi@",
+			want: s("bocchi", "@ "),
+		},
 	}
 	for _, c := range cases {
 		t.Run(c.name, func(t *testing.T) {