From 1d6213636e6b3cecad74fa7af19a9e0e81788aab Mon Sep 17 00:00:00 2001
From: Humza Shahid <humzasaur@gmail.com>
Date: Wed, 8 Oct 2025 06:24:40 +0100
Subject: [PATCH] add function to line_gap.sml to check if iterator is at end

---
 src/line_gap.sml | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/line_gap.sml b/src/line_gap.sml
index 418e409..3aa1e71 100644
--- a/src/line_gap.sml
+++ b/src/line_gap.sml
@@ -40,6 +40,7 @@ sig
   val makeStringIterator: t -> string_iterator
   val moveIteratorToIdx: int * string_iterator -> string_iterator
   val subIterator: int * string_iterator -> char
+  val isIteratorAtEnd: string_iterator -> bool
 
   (* for testing *)
   val verifyIndex: t -> unit
@@ -3382,6 +3383,9 @@ struct
     else
       moveIteratorRight (findIdx, idx, leftStrings, rightStrings)
 
+  fun isIteratorAtEnd {idx = _, leftStrings = _, rightStrings} =
+    List.null rightStrings
+
   fun subIterator (findIdx, {idx, leftStrings, rightStrings}) =
     if findIdx >= idx then
       case rightStrings of