Convert user defined Go language struct into raw sql

main.go

package main

import (
	"fmt"
	"strings"
)

type Node struct {
	Name     string
	Value    *string
	Children []*Node
}

func main() {
	planner := "planner"
	osio := "openshiftio"
	rhel := "rhel"
	a := Node{
		Name:  "OR",
		Value: nil,
		Children: []*Node{
			&Node{
				Name:  "AND",
				Value: nil,
				Children: []*Node{
					&Node{
						Name:     "space",
						Value:    &osio,
						Children: nil,
					},
					&Node{
						Name:     "area",
						Value:    &planner,
						Children: nil,
					},
				},
			},
			&Node{
				Name:     "space",
				Value:    &rhel,
				Children: nil,
			},
		},
	}

	b := Node{
		Name:  "AND",
		Value: nil,
		Children: []*Node{
			&Node{
				Name:     "space",
				Value:    &osio,
				Children: nil,
			}, &Node{
				Name:     "area",
				Value:    &planner,
				Children: nil,
			},
		},
	}

	fmt.Println(generateExpression(&a))
	fmt.Println(generateExpression(&b))
}

func isOperator(str string) bool {
	return str == "AND" || str == "OR"
}

func generateExpression(n *Node) string {
	var query string
	var expr []string
	currentOperator := n.Name
	if !isOperator(currentOperator) {
		q := fmt.Sprintf("( %s = %s )", n.Name, *n.Value)
		expr = append(expr, q)
	}
	for _, child := range n.Children {
		if isOperator(child.Name) {
			q := generateExpression(child)
			q = fmt.Sprintf(" ( %s ) ", q)
			expr = append(expr, q)
		} else {
			q := fmt.Sprintf(" ( %s = %s ) ", child.Name, *child.Value)
			expr = append(expr, q)
		}
	}
	query = strings.Join(expr, currentOperator)
	return query
}

//$ go run main.go 
// (  ( space = openshiftio ) AND ( area = planner )  ) OR ( space = rhel ) 
// ( space = openshiftio ) AND ( area = planner )