I'm trying to better understand how to properly use interfaces and created
this scenario:
Let's say I have an 'evaluator' program, that over time will want to add
more and more evaluations of a Go-NoGo nature (Nasa?)
Here's want I was trying:
// My Go-NoGo interface - method should return true/false and an error is
false
type GoNoGoer interface {
Eval() (bool, error)
}
Here's a couple of concrete evaluation types:
----------
type Evaluation1 struct {
Data string
}
func (a *Evaluation1) Eval() (bool, error) {
isOk := a.DoMyEvaluationWithTheData()
if !isOk {
return false, fmt.Errorf("evaluation failed because ...")
}
return true, nil
}
type Evaluation2 struct {
SomeData string
MoreData int64
}
func (a *Evaluation2) Eval() (bool, error) {
isOk := a.DoMyEvaluationWithTheStructData()
if !isOk {
return false, fmt.Errorf("evaluation failed because ...")
}
return true, nil
}
----------
In main - iterate over all the evaluations and print the results of Eval()
func main() {
one := Evaluation1{Data: "abcabcabc"}
two := Evaluation2{SomeData: "xyzxyz", MoreDate: 128}
var evals []interface{} <------ So I want a slice of evaluations
(all implemented as various structs) - probably not correct to use
interface{}???
evals = append(evals, one)
evals = append(evals, two)
// range over the slice, and if the object has implemented the Eval()
method execute it and print the results (doesn't work)
for _, eval := range evals {
if ok := eval.(GoNoGoer); ok { <-- This also is wrong, I want to go the
other direction (from concrete to interface)
isOk, err := eval.Eval()
fmt.Println(ok, err)
}
}
}
I'd appreciate the slap across the head pointing out where I'm missing the
boat!
TIA
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