From cf4d305b319e866a712be691b5088683084f73fd Mon Sep 17 00:00:00 2001
From: Aadhavan Srinivasan <aadhavan@twomorecents.org>
Date: Fri, 24 Jan 2025 14:58:07 -0500
Subject: [PATCH] Allow hyphen to be escaped inside character class

---
 postfixNode.go | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/postfixNode.go b/postfixNode.go
index b8318f8..2809b45 100644
--- a/postfixNode.go
+++ b/postfixNode.go
@@ -116,6 +116,13 @@ func newEscapedNode(c rune, inCharClass bool) (postfixNode, error) {
 	case 'v': // Vertical tab
 		toReturn.nodetype = CHARACTER
 		toReturn.contents = append(toReturn.contents, rune(11))
+	case '-': // Literal hyphen - only in character class
+		if inCharClass {
+			toReturn.nodetype = CHARACTER
+			toReturn.contents = append(toReturn.contents, '-')
+		} else {
+			return postfixNode{}, fmt.Errorf("Invalid escape character.")
+		}
 	default: // None of the above - append it as a regular character
 		if isNormalChar(c) { // Normal characters cannot be escaped
 			return postfixNode{}, fmt.Errorf("Invalid escape character.")