From 22858219b44dcc483aecc40297cea28a02625972 Mon Sep 17 00:00:00 2001
From: Peter Mikkelsen <petermikkelsen10@gmail.com>
Date: Fri, 28 Jan 2022 15:40:40 +0000
Subject: =?UTF-8?q?Implement=20membership=20(X=E2=88=8AY),=20excluding=20(?=
 =?UTF-8?q?X~Y)=20and=20union=20(X=E2=88=AAY)?=
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---
 functions.c | 27 ++++++++++++++++++++++++---
 1 file changed, 24 insertions(+), 3 deletions(-)

(limited to 'functions.c')

diff --git a/functions.c b/functions.c
index eedacb9..ad87c11 100644
--- a/functions.c
+++ b/functions.c
@@ -102,11 +102,11 @@ fndyad dyadfunctiondefs[] = {
 	0, /* ⍒ */
 	0, /* ⍳ */
 	0, /* ⍸ */
-	0, /* ∊ */
+	fnMembership, /* ∊ */
 	0, /* ⍷ */
-	0, /* ∪ */
+	fnUnion, /* ∪ */
 	0, /* ∩ */
-	0, /* ~ */
+	fnExcluding, /* ~ */
 	fnCatenateLast, /* , */
 	fnCatenateFirst, /* ⍪ */
 	fnReshape, /* ⍴ */
@@ -1136,6 +1136,27 @@ fnIndex(Array *left, Array *right)
 	return result;
 }
 
+Array *
+fnMembership(Array *left, Array *right)
+{
+	/* TODO avoid outer product */
+	return rundfn(L"∨/⍺≡⌾⍵", nil, nil, left, right);
+}
+
+Array *
+fnUnion(Array *left, Array *right)
+{
+	if(left->rank > 1 || right->rank > 1)
+		throwerror(nil, ERank);
+	return rundfn(L"⍺⍪⍵~⍺", nil, nil, left, right);
+}
+
+Array *
+fnExcluding(Array *left, Array *right)
+{
+	return rundfn(L"(~⍺∊⍵)⌿⍺", nil, nil, left, right);
+}
+
 Array *
 fnCatenateLast(Array *left, Array *right)
 {
-- 
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