From 66d0374a232c7fb7c3d443b081ae231ea249511a Mon Sep 17 00:00:00 2001
From: Marshall Lochbaum <mwlochbaum@gmail.com>
Date: Mon, 3 Aug 2020 12:52:34 -0400
Subject: Iterative version of Indices

---
 impl.bqn | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/impl.bqn b/impl.bqn
index 8579e2b5..4a1c82bb 100644
--- a/impl.bqn
+++ b/impl.bqn
@@ -66,6 +66,17 @@ match←{(0⊑𝕨)◶(1⊑𝕨)‿𝕩}´⟨
   {1×´⥊𝕨Match¨𝕩}
 ⟩
 
+Indices←{
+  ! 1==𝕩
+  l←≠𝕩
+  {
+    ! 1×´Nat¨𝕩
+    es ← +`𝕩 ⋄ e←0 ⋄ Ei←{e↩𝕩⊑es}
+    Ei i←0
+    {j←𝕩⋄U←{U⍟(j=Ei)1+𝕩}⋄{i↩U𝕩}⍟(𝕩=e)i}¨↕(l-1)⊑es
+  }⍟(0<l)𝕩
+}
+
 + ↩ + _perv
 - ↩ - _perv
 × ↩ (0⊸(<->) ⊘ ×) _perv
@@ -232,11 +243,6 @@ Windows←{
 Reverse ← {!1≤=𝕩 ⋄ (-↕⊸¬≠𝕩)⊏𝕩}
 Rotate ← {!Int𝕨 ⋄ l←≠𝕩⋄(l|𝕨+↕l)⊏𝕩} _onAxes_ 0
 
-Indices←{
-  ! 1==𝕩
-  ! ∧´Nat¨𝕩
-  ⟨⟩∾´𝕩⥊¨↕≠𝕩
-}
 Rep ← Indices⊸⊏
 Replicate ← {0<=𝕨}◶(⥊˜⟜≠Rep⊢)‿{!𝕨=○≠𝕩⋄𝕨Rep𝕩} _onAxes_ (1-0=≠)
 
-- 
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