From 4e25e065a41d88ae9b58378957c8c6de9b7545c6 Mon Sep 17 00:00:00 2001
From: David Thompson <dthompson2@worcester.edu>
Date: Fri, 5 Mar 2021 08:27:38 -0500
Subject: utils: Handle negative increment in for-range.

---
 chickadee/utils.scm | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

(limited to 'chickadee/utils.scm')

diff --git a/chickadee/utils.scm b/chickadee/utils.scm
index e2a20c1..8869e8d 100644
--- a/chickadee/utils.scm
+++ b/chickadee/utils.scm
@@ -40,11 +40,12 @@
             (e end)
             (reverse? (< e s))
             (start* (if reverse? e s))
-            (end* (if reverse? s e)))
+            (end* (if reverse? s e))
+            (inc* (abs inc)))
        (let loop ((var start*))
          (when (< var end*)
            body ...
-           (loop (+ var inc))))))
+           (loop (+ var inc*))))))
     ((_ ((var end start)) body ...)
      (for-range ((var end start 1)) body ...))
     ((_ ((var end)) body ...)
-- 
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