From 663f9df8c3ddef75ff1102a14a0e89f032fc6858 Mon Sep 17 00:00:00 2001
From: Nat Quayle Nelson <natquaylenelson@gmail.com>
Date: Mon, 29 Nov 2021 15:54:39 -0700
Subject: [PATCH] Prelude.substr allow negative indices

---
 kiss/src/kiss/Kiss.hx    |  1 +
 kiss/src/kiss/Prelude.hx | 10 ++++++++++
 2 files changed, 11 insertions(+)

diff --git a/kiss/src/kiss/Kiss.hx b/kiss/src/kiss/Kiss.hx
index 48786922..67f15238 100644
--- a/kiss/src/kiss/Kiss.hx
+++ b/kiss/src/kiss/Kiss.hx
@@ -111,6 +111,7 @@ class Kiss {
                 "zipThrow" => Symbol("Prelude.zipThrow"),
                 "joinPath" => Symbol("Prelude.joinPath"),
                 "readDirectory" => Symbol("Prelude.readDirectory"),
+                "substr" => Symbol("Prelude.substr")
             ],
             fieldList: [],
             fieldDict: new Map(),
diff --git a/kiss/src/kiss/Prelude.hx b/kiss/src/kiss/Prelude.hx
index 6e49997c..88682f5a 100644
--- a/kiss/src/kiss/Prelude.hx
+++ b/kiss/src/kiss/Prelude.hx
@@ -632,6 +632,16 @@ class Prelude {
     }
     #end
 
+    public static function substr(str:String, startIdx:Int, ?endIdx:Int) {
+        function negIdx(idx) {
+            return if (idx < 0) str.length + idx else idx;
+        }
+
+        if (endIdx == null) endIdx = str.length;
+
+        return str.substr(negIdx(startIdx), negIdx(endIdx));
+    }
+
     public static var newLine = "\n";
     public static var backSlash = "\\";
 }