Add under ⍢ and obverse ⍫

Teach inverse() that the inverse of f⍫g is g⍫f


1 files changed, 22 insertions, 1 deletions

diff --git a/operators.c b/operators.c
index 1ecb8aa..2d26251 100644
--- a/operators.c
+++ b/operators.c
@@ -5,7 +5,7 @@
 #include "apl9.h"
 
 Rune primmonopnames[] = L"¨⍨⌸⌶&∆";
-Rune primdyadopnames[] = L"⍣.∘⍤⍥@⍠⌺⍙";
+Rune primdyadopnames[] = L"⍣.∘⍤⍥@⍠⌺⍢⍫⍙";
 
 opmonad monadoperatordefs[] = {
 	opEach, /* ¨ */
@@ -25,6 +25,8 @@ opdyad dyadoperatordefs[] = {
 	0, /* @ */
 	0, /* ⍠ */
 	0, /* ⌺ */
+	opUnder, /* ⍢ */
+	opObverse, /* ⍫ */
 	opSelfReference2, /* ⍙ */
 };
 
@@ -191,6 +193,25 @@ opAtop(Datum *lefto, Datum *righto, Array *left, Array *right)
 }
 
 Array *
+opUnder(Datum *lefto, Datum *righto, Array *left, Array *right)
+{
+	if(lefto->tag != FunctionTag || righto->tag != FunctionTag)
+		throwerror(L"⍢ operands must be functions", EDomain);
+	if(left)
+		return rundfn(L"⍹⍣¯1 ⊢ (⍹ ⍺) ⍶ ⍹ ⍵", lefto, righto, left, right);
+	else
+		return rundfn(L"⍹⍣¯1 ⍶ ⍹ ⍵", lefto, righto, left, right);
+}
+
+Array *
+opObverse(Datum *lefto, Datum *righto, Array *left, Array *right)
+{
+	if(lefto->tag != FunctionTag || righto->tag != FunctionTag)
+		throwerror(L"⍫ operands must be functions", EDomain);
+	return runfunc(lefto->func, left, right);
+}
+
+Array *
 opOver(Datum *lefto, Datum *righto, Array *left, Array *right)
 {
 	if(lefto->tag != FunctionTag || righto->tag != FunctionTag)