wip

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

@@ -0,0 +1,41 @@
+package optimizer
+
+import (
+	. "github.com/antonmedv/expr/ast"
+)
+
+type inRange struct{}
+
+func (*inRange) Enter(*Node) {}
+func (*inRange) Exit(node *Node) {
+	switch n := (*node).(type) {
+	case *BinaryNode:
+		if n.Operator == "in" || n.Operator == "not in" {
+			if rng, ok := n.Right.(*BinaryNode); ok && rng.Operator == ".." {
+				if from, ok := rng.Left.(*IntegerNode); ok {
+					if to, ok := rng.Right.(*IntegerNode); ok {
+						Patch(node, &BinaryNode{
+							Operator: "and",
+							Left: &BinaryNode{
+								Operator: ">=",
+								Left:     n.Left,
+								Right:    from,
+							},
+							Right: &BinaryNode{
+								Operator: "<=",
+								Left:     n.Left,
+								Right:    to,
+							},
+						})
+						if n.Operator == "not in" {
+							Patch(node, &UnaryNode{
+								Operator: "not",
+								Node:     *node,
+							})
+						}
+					}
+				}
+			}
+		}
+	}
+}