diff --git a/operator-digest.go b/operator-digest.go
index 632e26f..5ac9e88 100644
--- a/operator-digest.go
+++ b/operator-digest.go
@@ -43,8 +43,8 @@ func evalDigest(ctx kern.ExprContext, opTerm *term) (v any, err error) {
 	lastValue = nil
 	for item, err = it.Next(); err == nil; item, err = it.Next() {
 		ctx.SetVar("_", item)
-		ctx.SetVar("_index", it.Index())
-		ctx.SetVar("_count", it.Count())
+		ctx.SetVar("__", it.Index())
+		ctx.SetVar("_#", it.Count())
 		if rightValue, err = opTerm.children[1].Compute(ctx); err == nil {
 			if rightValue == nil {
 				break
@@ -52,8 +52,8 @@ func evalDigest(ctx kern.ExprContext, opTerm *term) (v any, err error) {
 				lastValue = rightValue
 			}
 		}
-		ctx.DeleteVar("_count")
-		ctx.DeleteVar("_index")
+		ctx.DeleteVar("_#")
+		ctx.DeleteVar("__")
 		ctx.DeleteVar("_")
 		if err != nil {
 			break
diff --git a/operator-filter.go b/operator-filter.go
index b8652c0..875aaa9 100644
--- a/operator-filter.go
+++ b/operator-filter.go
@@ -43,8 +43,8 @@ func evalFilter(ctx kern.ExprContext, opTerm *term) (v any, err error) {
 	values := kern.NewListA()
 	for item, err = it.Next(); err == nil; item, err = it.Next() {
 		ctx.SetVar("_", item)
-		ctx.SetVar("_index", it.Index())
-		ctx.SetVar("_count", it.Count())
+		ctx.SetVar("__", it.Index())
+		ctx.SetVar("_#", it.Count())
 		if rightValue, err = opTerm.children[1].Compute(ctx); err == nil {
 			if success, valid := kern.ToBool(rightValue); valid {
 				if success {
@@ -54,8 +54,8 @@ func evalFilter(ctx kern.ExprContext, opTerm *term) (v any, err error) {
 				err = fmt.Errorf("filter expression must return a boolean or a castable to boolean, got %v [%T]", rightValue, rightValue)
 			}
 		}
-		ctx.DeleteVar("_count")
-		ctx.DeleteVar("_index")
+		ctx.DeleteVar("_#")
+		ctx.DeleteVar("__")
 		ctx.DeleteVar("_")
 		if err != nil {
 			break
diff --git a/operator-map.go b/operator-map.go
index d7c81a5..91b6a7b 100644
--- a/operator-map.go
+++ b/operator-map.go
@@ -43,13 +43,13 @@ func evalMap(ctx kern.ExprContext, opTerm *term) (v any, err error) {
 	values := kern.NewListA()
 	for item, err = it.Next(); err == nil; item, err = it.Next() {
 		ctx.SetVar("_", item)
-		ctx.SetVar("_index", it.Index())
-		ctx.SetVar("_count", it.Count())
+		ctx.SetVar("__", it.Index())
+		ctx.SetVar("_#", it.Count())
 		if rightValue, err = opTerm.children[1].Compute(ctx); err == nil {
 			values.AppendItem(rightValue)
 		}
-		ctx.DeleteVar("_count")
-		ctx.DeleteVar("_index")
+		ctx.DeleteVar("_#")
+		ctx.DeleteVar("__")
 		ctx.DeleteVar("_")
 		if err != nil {
 			break
diff --git a/t_iterator_test.go b/t_iterator_test.go
index a3b0c72..84d62bb 100644
--- a/t_iterator_test.go
+++ b/t_iterator_test.go
@@ -35,7 +35,7 @@ func TestIteratorParser(t *testing.T) {
 		/*  20 */ {`it=$({1:"one",2:"two",3:"three"}, "default", "value"); it++`, "one", nil},
 		/*  21 */ {`it=$({1:"one",2:"two",3:"three"}, "desc", "key"); it++`, int64(3), nil},
 		/*  22 */ {`it=$({1:"one",2:"two",3:"three"}, "asc", "item"); it++`, kern.NewList([]any{int64(1), "one"}), nil},
-		/*  23 */ {`builtin "os.file"; fileReadIterator("test-file.txt") map ${_index}`, kern.NewList([]any{int64(0), int64(1)}), nil},
+		/*  23 */ {`builtin "os.file"; fileReadIterator("test-file.txt") map ${__}`, kern.NewList([]any{int64(0), int64(1)}), nil},
 		/*  24 */ {`builtin "os.file"; #(fileReadIterator("test-file.txt") filter (#${_} == 2))`, int64(0), nil},
 		/*  25 */ {`builtin "os.file"; #(fileReadIterator("test-file.txt") filter (#${_} == 3))`, int64(2), nil},
 		/*  26 */ {`#($(10) map ${_})`, int64(10), nil},
@@ -43,6 +43,7 @@ func TestIteratorParser(t *testing.T) {
 		/*  28 */ {`$(10) digest ${_}`, int64(9), nil},
 		/*  29 */ {`$(10,0) digest ${_}`, int64(1), nil},
 		/*  30 */ {`$(10,0,-2) digest ${_}`, int64(2), nil},
+		/*  31 */ {`[3,4,5] map ${_#}`, kern.NewList([]any{int64(1), int64(2), int64(3)}), nil},
 	}
 
 	// runTestSuiteSpec(t, section, inputs, 10)