I have developed a library that depends very much on reflect package. It
caches a specific type and return a function that encodes(does something
with) with that kind /type of data. Think of defining database schema using
types and generating functions to validate/update/insert data.
I reduced it to a basic example below. Can the generics feature from Go
help me make it any safer? Ideally I would like to make the program below*
not to compile *due the errors of invalid params passed to *PrintT* instead
to throw dynamically at runtime.
package main
import (
"errors"
"fmt"
"reflect"
)
type T struct {
F1 string
F2 int
}
type T2 struct {
F1 float32
F2 bool
}
var PrintT = Function(T{})
func main() {
if err := PrintT("one", 1); err != nil {
fmt.Printf("err %v", err)
}
if err := PrintT("one", 1, "another"); err != nil {
fmt.Printf("err %v", err)
}
if err := PrintT("one", "one"); err != nil {
fmt.Printf("err %v", err)
}
}
type ReturnFunc func(params ...interface{}) error
func Function(v interface{}) ReturnFunc {
var paramTypes []reflect.Type
tv := reflect.TypeOf(v)
for i := 0; i < tv.NumField(); i++ {
paramTypes = append(paramTypes, tv.Field(i).Type)
}
fn := func(param ...interface{}) error {
// validate input
if len(param) != len(paramTypes) {
return errors.New("invalid number of params passed")
}
for k, v := range param {
if reflect.TypeOf(v) != paramTypes[k] {
return errors.New("invalid type passed")
}
}
// do something with the params
fmt.Println(param...)
return nil
}
return fn
}
https://go2goplay.golang.org/p/1MJynmFhq6B
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