From 7248a3e27f18dba05ac6d5696db4554be88d4e42 Mon Sep 17 00:00:00 2001
From: Humza Shahid <humzasaur@gmail.com>
Date: Wed, 8 Oct 2025 06:17:01 +0100
Subject: [PATCH] add function to get a char from a string_iterator in
 line_gap.sml

---
 src/line_gap.sml | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/src/line_gap.sml b/src/line_gap.sml
index 4cf301d..418e409 100644
--- a/src/line_gap.sml
+++ b/src/line_gap.sml
@@ -39,6 +39,7 @@ sig
 
   val makeStringIterator: t -> string_iterator
   val moveIteratorToIdx: int * string_iterator -> string_iterator
+  val subIterator: int * string_iterator -> char
 
   (* for testing *)
   val verifyIndex: t -> unit
@@ -3381,6 +3382,16 @@ struct
     else
       moveIteratorRight (findIdx, idx, leftStrings, rightStrings)
 
+  fun subIterator (findIdx, {idx, leftStrings, rightStrings}) =
+    if findIdx >= idx then
+      case rightStrings of
+        hd :: tl => subRight (findIdx, idx, hd, tl)
+      | [] => raise Fail "not found"
+    else
+      case leftStrings of
+        hd :: tl => subLeft (findIdx, idx, hd, tl)
+      | [] => raise Fail "not found"
+
   (* TEST CODE *)
   local
     fun lineBreaksToString vec =