Add sum(map()) optimization

optimizer/optimizer.go

@@ -37,5 +37,6 @@ func Optimize(node *Node, config *conf.Config) error {
 	Walk(node, &filterLast{})
 	Walk(node, &filterFirst{})
 	Walk(node, &predicateCombination{})
+	Walk(node, &sumMap{})
 	return nil
 }

optimizer/sum_map.go

@@ -0,0 +1,25 @@
+package optimizer
+
+import (
+	. "github.com/expr-lang/expr/ast"
+)
+
+type sumMap struct{}
+
+func (*sumMap) Visit(node *Node) {
+	if sumBuiltin, ok := (*node).(*BuiltinNode); ok &&
+		sumBuiltin.Name == "sum" &&
+		len(sumBuiltin.Arguments) == 1 {
+		if mapBuiltin, ok := sumBuiltin.Arguments[0].(*BuiltinNode); ok &&
+			mapBuiltin.Name == "map" &&
+			len(mapBuiltin.Arguments) == 2 {
+			Patch(node, &BuiltinNode{
+				Name: "sum",
+				Arguments: []Node{
+					mapBuiltin.Arguments[0],
+					mapBuiltin.Arguments[1],
+				},
+			})
+		}
+	}
+}

optimizer/sum_map_test.go

@@ -0,0 +1,35 @@
+package optimizer_test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/expr-lang/expr/ast"
+	"github.com/expr-lang/expr/optimizer"
+	"github.com/expr-lang/expr/parser"
+)
+
+func TestOptimize_sum_map(t *testing.T) {
+	tree, err := parser.Parse(`sum(map(users, {.Age}))`)
+	require.NoError(t, err)
+
+	err = optimizer.Optimize(&tree.Node, nil)
+	require.NoError(t, err)
+
+	expected := &ast.BuiltinNode{
+		Name: "sum",
+		Arguments: []ast.Node{
+			&ast.IdentifierNode{Value: "users"},
+			&ast.ClosureNode{
+				Node: &ast.MemberNode{
+					Node:     &ast.PointerNode{},
+					Property: &ast.StringNode{Value: "Age"},
+				},
+			},
+		},
+	}
+
+	assert.Equal(t, ast.Dump(expected), ast.Dump(tree.Node))
+}

test/fuzz/fuzz_corpus.txt

@@ -5608,7 +5608,6 @@ findLastIndex(list, f64 == f64)
 findLastIndex(list, false == false)
 findLastIndex(list, false and false)
 findLastIndex(list, false and ok)
-findLastIndex(list, false) != i
 findLastIndex(list, foo != #)
 findLastIndex(list, foo == foo)
 findLastIndex(list, greet != half)