From 6b9782ce4a36e93156426b5747efcc90401b6251 Mon Sep 17 00:00:00 2001
From: Jan Tuomi <jans.tuomi@gmail.com>
Date: Tue, 6 Dec 2022 21:18:18 +0200
Subject: Add core/result.milch

---
 core/common.milch | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

(limited to 'core/common.milch')

diff --git a/core/common.milch b/core/common.milch
index 55fa2b8..2aa72a2 100644
--- a/core/common.milch
+++ b/core/common.milch
@@ -141,11 +141,18 @@
 (let split-by (\[delim vals]
     (_split-by delim [] vals)))
 
-(let at (\[n seq]
+(let at! (\![n seq]
     (match seq
-        []          (fatal! (fmt "at out of bounds, n: {0}" [n]))
+        []          (fatal! (fmt "at out of bounds, index: {0}" [n]))
         otherwise   (match n
             0           (head seq)
+            otherwise   (at! (- n 1) (tail seq))))))
+
+(let at (\[n seq]
+    (match seq
+        []          (Result/ex (fmt "at out of bounds, index: {0}" [n]))
+        otherwise   (match n
+            0           (Result/ok (head seq))
             otherwise   (at (- n 1) (tail seq))))))
 
 (let maximum (\[vals]
-- 
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