Parentheses disappear for conditional node

[aizeNR]

Hi, when you build a tree with a conditional expression, and convert it to a tree and back to an expression, the parentheses for the conditional disappear.

Below is code to reproduce
https://go.dev/play/p/mHo7-d3vFuo

package main

import (
	"fmt"

	"github.com/expr-lang/expr/parser"
)

func main() {
	tree, err := parser.Parse("(UserID != 0 ? true : false) && ProductID == 1")
	if err != nil {
		fmt.Print(err.Error())
		return
	}

	fmt.Print(tree.Node.String())
}

[zhuliquan]

may be below branch will help you
https://github.com/expr-lang/expr/tree/feature-parenthesis-node

[antonmedv]

I will fix it.

[antonmedv]

Fixed.