go-eek
Blazingly fast and safe go evaluation library, created on top of Go pkg/plugin package.
On go-eek, the eval expression is encapsulated into a single function, and stored in a go file. The go file later on will be build into a plugin file (*.so file). And then next, for every evaluation call, it will happen in the plugin file. This is why go-eek is insanely fast.
go-eek accept standar Go syntax expression.
Example
Simple Example
import . "github.com/novalagung/go-eek"
// create new eek object and name it
obj := New()
obj.SetName("simple operation")
// define variables (and default value of particular variable if available)
obj.DefineVariable(Var{Name: "VarA", Type: "int"})
obj.DefineVariable(Var{Name: "VarB", Type: "float64", DefaultValue: 10.5})
// specify the evaluation expression in go standard syntax
obj.PrepareEvaluation(`
castedVarA := float64(VarA)
VarC := castedVarA + VarB
return VarC
`)
// build only need to happen once
err := obj.Build()
if err != nil {
log.Fatal(err)
}
// evaluate!
output1, _ := obj.Evaluate(ExecVar{ "VarA": 9 })
fmt.Println("with VarA = 9, the result will be", output1)
output2, _ := obj.Evaluate(ExecVar{ "VarA": 12, "VarB": 12.4 })
fmt.Println("with VarA = 12 and VarB = 12.4, the result will be", output2)More Complex Example
obj := eek.New("evaluation with 3rd party library")
obj.ImportPackage("fmt")
obj.ImportPackage("github.com/novalagung/gubrak")
obj.DefineVariable(eek.Var{Name: "VarMessageWin", Type: "string", DefaultValue: "Congrats! You win the lottery!"})
obj.DefineVariable(eek.Var{Name: "VarMessageLose", Type: "string", DefaultValue: "You lose"})
obj.DefineVariable(eek.Var{Name: "VarYourLotteryCode", Type: "int"})
obj.DefineVariable(eek.Var{Name: "VarRepeatUntil", Type: "int", DefaultValue: 5})
obj.PrepareEvaluation(`
generateRandomNumber := func() int {
return gubrak.RandomInt(0, 10)
}
i := 0
for i < VarRepeatUntil {
if generateRandomNumber() == VarYourLotteryCode {
return fmt.Sprintf("%s after %d tried", VarMessageWin, i + 1)
}
i++
}
return VarMessageLose
`)
err := obj.Build()
if err != nil {
log.Fatal(err)
}
output, _ = obj.Evaluate(eek.ExecVar{
"VarYourLotteryCode": 3,
"VarRepeatUntil": 10,
})
fmt.Println("output:", output)Arithmethic expression Example
obj := New("aritmethic expressions")
obj.DefineVariable(eek.Var{Name: "VarN", Type: "int"})
obj.DefineFunction(eek.Func{
Name: "IF",
BodyFunction: `
func(cond bool, ok, nok string) string {
if cond {
return ok
} else {
return nok
}
}
`,
})
obj.DefineFunction(eek.Func{
Name: "OR",
BodyFunction: `
func(cond1, cond2 bool) bool {
return cond1 || cond2
}
`,
})
obj.DefineFunction(eek.Func{
Name: "NOT",
BodyFunction: `func(cond bool) bool { return !cond }`,
})
obj.PrepareEvaluation(`
result := IF(VarN>20,IF(OR(VarN>40,N==40),IF(VarN>60,IF(NOT(VarN>80),"good",IF(VarN==90,"perfect","terrific")),"ok"),"ok, but still bad"),"bad")
return result
`)
err := obj.Build()
if err != nil {
log.Fatal(err)
}
output, _ := obj.Evaluate(eek.ExecVar{"VarN": 76})
fmt.Println(output)More example available on the *_test.go file.
Documentation
Author
Noval Agung Prayog
License
MIT License