Implement scans ⍀ and \

1 files changed, 46 insertions, 2 deletions

diff --git a/hybrids.c b/hybrids.c
index 39f3f7a..00977da 100644
--- a/hybrids.c
+++ b/hybrids.c
@@ -15,9 +15,9 @@ fndyad hybridfunctiondefs[] = {
 
 opmonad hybridoperatordefs[] = {
 	opReduceLast, /* / */
-	0, /* \ */
+	opScanLast, /* \ */
 	opReduceFirst, /* ⌿ */
-	0, /* ⍀ */
+	opScanFirst, /* ⍀ */
 };
 
 /* function definitions */
@@ -38,6 +38,20 @@ opReduceLast(Datum *lefto, Array *left, Array *right)
 }
 
 Array *
+opScanLast(Datum *lefto, Array *left, Array *right)
+{
+	if(left)
+		throwerror(L"f\ doesn't take a left argument", ESyntax);
+
+	right = fnTranspose(right);
+	Array *tmp = opScanFirst(lefto, left, right);
+	Array *res = fnTranspose(tmp);
+	freearray(right);
+	freearray(tmp);
+	return res;
+}
+
+Array *
 opReduceFirst(Datum *lefto, Array *left, Array *right)
 {
 	if(left)
@@ -80,5 +94,35 @@ opReduceFirst(Datum *lefto, Array *left, Array *right)
 		index->arraydata[index->size-1]->intdata[0]++;
 	}
 	freearray(index);
+
 	return result;
 }
+
+Array *
+opScanFirst(Datum *lefto, Array *left, Array *right)
+{
+	if(left)
+		throwerror(L"f⍀ doesn't take a left argument", ESyntax);
+
+	Array *result = allocarray(AtypeArray, right->rank, right->size);
+	for(int i = 0; i < right->rank; i++)
+		result->shape[i] = right->shape[i];
+
+	int n = result->shape[0];
+	int m = result->size / n;
+	for(int i = 0; i < n; i++){
+		Array *len = mkscalarint(i + 1);
+		Array *index = fnIndexGenerator(len);
+		Array *ix = fnEnclose(index);
+		Array *subarr = fnIndex(ix, right);
+		Array *subres = opReduceFirst(lefto, left, subarr);
+		for(int j = 0; j < m; j++)
+			result->arraydata[i*m + j] = arrayitem(subres, j);
+		freearray(len);
+		freearray(index);
+		freearray(ix);
+		freearray(subarr);
+		freearray(subres);
+	}
+	return result;
+}
\ No newline at end of file