govaluate_pseudo_functions.go

package main

import (
	"log"

	"github.com/Knetic/govaluate"
)

type parametersImpl struct {
	get func(name string) (interface{}, error)
}

func (p *parametersImpl) Get(name string) (interface{}, error) {
	return p.get(name)
}

func main() {
	expression, err := govaluate.NewEvaluableExpression(`[count:"rack_.*"] < 3 || [replicas:\[first:"rack_.*"\]] < 3`)
	if err != nil {
		log.Fatal(err)
	}
	result, err := expression.Eval(&parametersImpl{
		func(name string) (interface{}, error) {
			log.Printf("parameter %q", name)
			return 1, nil
		},
	})
	if err != nil {
		log.Fatal(err)
	}
	log.Printf("output %+v", result)
}

z output

 ~/Developer/govaluate-test  go run main.go
2016/07/05 22:12:41 parameter "count:\"rack_.*\""
2016/07/05 22:12:41 parameter "replicas:[first:\"rack_.*\"]"
2016/07/05 22:12:41 output true