Added with operator

pkg/yqlib/operator_with.go

@@ -0,0 +1,30 @@
+package yqlib
+
+import "fmt"
+
+func withOperator(d *dataTreeNavigator, context Context, expressionNode *ExpressionNode) (Context, error) {
+	log.Debugf("-- withOperator")
+	// with(path, exp)
+
+	if expressionNode.Rhs.Operation.OperationType != blockOpType {
+		return Context{}, fmt.Errorf("with must be given a block, got %v instead", expressionNode.Rhs.Operation.OperationType.Type)
+	}
+
+	pathExp := expressionNode.Rhs.Lhs
+
+	updateContext, err := d.GetMatchingNodes(context, pathExp)
+
+	if err != nil {
+		return Context{}, err
+	}
+
+	updateExp := expressionNode.Rhs.Rhs
+
+	_, err = d.GetMatchingNodes(updateContext, updateExp)
+	if err != nil {
+		return Context{}, err
+	}
+
+	return context, nil
+
+}