From 603354a02e03c6bf36a572a0f2ca8a8c60f75055 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Bj=C3=B6rn=20Lindqvist?= <bjourne@gmail.com>
Date: Thu, 8 Feb 2018 19:39:31 +0100
Subject: [PATCH] sequences.extras: this formulation of arg-max/min should be
 better

---
 extra/sequences/extras/extras-docs.factor  | 10 ++++++++++
 extra/sequences/extras/extras-tests.factor |  1 +
 extra/sequences/extras/extras.factor       |  4 ++--
 3 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/extra/sequences/extras/extras-docs.factor b/extra/sequences/extras/extras-docs.factor
index 3f77165e22..6e75c0307b 100644
--- a/extra/sequences/extras/extras-docs.factor
+++ b/extra/sequences/extras/extras-docs.factor
@@ -230,6 +230,16 @@ HELP: start-all*
                "{ 0 2 }"
     } } ;
 
+HELP: arg-max
+{ $values { "seq" sequence } { "n" integer } }
+{ $description "Outputs the sequence with the largest item." } ;
+
+HELP: arg-min
+{ $values { "seq" sequence } { "n" integer } }
+{ $description "Outputs the sequence with the smallest item." } ;
+
+{ arg-max arg-min } related-words
+
 HELP: count-subseq
 { $values
     { "subseq" sequence } { "seq" sequence } { "n" integer } }
diff --git a/extra/sequences/extras/extras-tests.factor b/extra/sequences/extras/extras-tests.factor
index 85a88798b4..880fbbd4ce 100644
--- a/extra/sequences/extras/extras-tests.factor
+++ b/extra/sequences/extras/extras-tests.factor
@@ -157,6 +157,7 @@ IN: sequences.extras.tests
 { { 1 3 5 } } [ 6 <iota> <odds> >array ] unit-test
 
 { 1 } [ { 1 7 3 7 6 3 7 } arg-max ] unit-test
+{ 2 } [ { 0 1 99 } arg-max ] unit-test
 { 0 } [ { 1 7 3 7 6 3 7 } arg-min ] unit-test
 { V{ 0 4 } } [ { 5 3 2 10 5 } [ 5 = ] arg-where ] unit-test
 { { 2 1 0 4 3 } } [ { 5 3 2 10 5 } arg-sort ] unit-test
diff --git a/extra/sequences/extras/extras.factor b/extra/sequences/extras/extras.factor
index c6943aa0f6..bf49f8c4d5 100644
--- a/extra/sequences/extras/extras.factor
+++ b/extra/sequences/extras/extras.factor
@@ -411,10 +411,10 @@ INSTANCE: odds immutable-sequence
     [ dup empty? ] swap until drop ; inline
 
 : arg-max ( seq -- n )
-    <enumerated> [ second-unsafe ] supremum-by first ;
+    [ supremum ] keep index ;
 
 : arg-min ( seq -- n )
-    <enumerated> [ second-unsafe ] infimum-by first ;
+    [ infimum ] keep index ;
 
 <PRIVATE
 
-- 
2.34.1