wip

vendor/github.com/antonmedv/expr/optimizer/in_array.go

@@ -0,0 +1,65 @@
+package optimizer
+
+import (
+	"reflect"
+
+	. "github.com/antonmedv/expr/ast"
+)
+
+type inArray struct{}
+
+func (*inArray) Enter(*Node) {}
+func (*inArray) Exit(node *Node) {
+	switch n := (*node).(type) {
+	case *BinaryNode:
+		if n.Operator == "in" || n.Operator == "not in" {
+			if array, ok := n.Right.(*ArrayNode); ok {
+				if len(array.Nodes) > 0 {
+					t := n.Left.Type()
+					if t == nil || t.Kind() != reflect.Int {
+						// This optimization can be only performed if left side is int type,
+						// as runtime.in func uses reflect.Map.MapIndex and keys of map must,
+						// be same as checked value type.
+						goto string
+					}
+
+					for _, a := range array.Nodes {
+						if _, ok := a.(*IntegerNode); !ok {
+							goto string
+						}
+					}
+					{
+						value := make(map[int]struct{})
+						for _, a := range array.Nodes {
+							value[a.(*IntegerNode).Value] = struct{}{}
+						}
+						Patch(node, &BinaryNode{
+							Operator: n.Operator,
+							Left:     n.Left,
+							Right:    &ConstantNode{Value: value},
+						})
+					}
+
+				string:
+					for _, a := range array.Nodes {
+						if _, ok := a.(*StringNode); !ok {
+							return
+						}
+					}
+					{
+						value := make(map[string]struct{})
+						for _, a := range array.Nodes {
+							value[a.(*StringNode).Value] = struct{}{}
+						}
+						Patch(node, &BinaryNode{
+							Operator: n.Operator,
+							Left:     n.Left,
+							Right:    &ConstantNode{Value: value},
+						})
+					}
+
+				}
+			}
+		}
+	}
+}