Implement monadic ⌽ and ⊖

2 files changed, 44 insertions, 2 deletions

diff --git a/apl9.h b/apl9.h
index f6ea693..b96e793 100644
--- a/apl9.h
+++ b/apl9.h
@@ -200,6 +200,8 @@ Array *fnNest(Array *);
 Array *fnIndexGenerator(Array *);
 Array *fnRavel(Array *);
 Array *fnShape(Array *);
+Array *fnReverseLast(Array *);
+Array *fnReverseFirst(Array *);
 
 /* Dyadic functions from function.c */
 Array *fnPlus(Array *, Array *);
diff --git a/functions.c b/functions.c
index 411f90b..ef9aa97 100644
--- a/functions.c
+++ b/functions.c
@@ -54,8 +54,8 @@ fnmonad monadfunctiondefs[] = {
 	fnRavel, /* , */
 	0, /* ⍪ */
 	fnShape, /* ⍴ */
-	0, /* ⌽ */
-	0, /* ⊖ */
+	fnReverseLast, /* ⌽ */
+	fnReverseFirst, /* ⊖ */
 	0, /* ⍉ */
 	0, /* ⍎ */
 	0, /* ⍕ */
@@ -226,6 +226,46 @@ fnShape(Array *right)
 	return res;
 }
 
+Array *
+fnReverseLast(Array *right)
+{
+	if(right->rank < 1)
+		return fnSame(right);
+
+	Array *res = duparray(right);
+
+	int nrows = 1;
+	int rowsize = res->shape[res->rank-1];
+	for(int i = 0; i < res->rank - 1; i++)
+		nrows *= res->shape[i];
+
+	for(int row = 0; row < nrows; row++){
+		for(int i = 0; i < rowsize; i++)
+			memcpy(
+				res->rawdata + (row * rowsize + i) * datasizes[res->type],
+				right->rawdata + ((1+row) * rowsize - 1 - i) * datasizes[res->type],
+				datasizes[res->type]);
+	}
+	return res;
+}
+
+Array *
+fnReverseFirst(Array *right)
+{
+	if(right->rank < 1 || right->shape[0] == 0)
+		return fnSame(right);
+
+	Array *res = duparray(right);
+	int cells = res->shape[0];
+	int elems = res->size / cells;
+	for(int i = 0; i < cells; i++)
+		memcpy(
+			res->rawdata + i * elems * datasizes[res->type],
+			right->rawdata + (cells - 1 - i) * elems * datasizes[res->type],
+			datasizes[res->type] * elems);
+	return res;
+}
+
 /* Dyadic functions */
 
 Array *