I would like to declare a variable which is a pointer to a function with an unknown signature.
For example, to declare a variable which can contain a pointer to a function which can be set to log.Printf I could go:
<code>var foo func(format string, v ...any)
</code>
<code>var foo func(format string, v ...any)
</code>
var foo func(format string, v ...any)
…
<code>foo = log.Printf
</code>
<code>foo = log.Printf
</code>
foo = log.Printf
But this assumes the function signature is known – in C++ I would use decltype but I can’t find anything similar in Go. I tried reflect but couldn’t make it work.
Anyone got any ideas?
Use reflection with interface, that way you will be able to use any function with interface. I made some changes and tested it on playground
<code>package main
import (
"log"
"reflect"
)
func main() {
var foo any = log.Printf
dynamicFunction(foo, "Pointer, %s!", "Test")
}
func dynamicFunction(fn any, args ...any) {
v := reflect.ValueOf(fn)
in := make([]reflect.Value, len(args))
for i, arg := range args {
in[i] = reflect.ValueOf(arg)
}
v.Call(in)
}
</code>
<code>package main
import (
"log"
"reflect"
)
func main() {
var foo any = log.Printf
dynamicFunction(foo, "Pointer, %s!", "Test")
}
func dynamicFunction(fn any, args ...any) {
v := reflect.ValueOf(fn)
in := make([]reflect.Value, len(args))
for i, arg := range args {
in[i] = reflect.ValueOf(arg)
}
v.Call(in)
}
</code>
package main
import (
"log"
"reflect"
)
func main() {
var foo any = log.Printf
dynamicFunction(foo, "Pointer, %s!", "Test")
}
func dynamicFunction(fn any, args ...any) {
v := reflect.ValueOf(fn)
in := make([]reflect.Value, len(args))
for i, arg := range args {
in[i] = reflect.ValueOf(arg)
}
v.Call(in)
}
https://go.dev/play/p/fdDwDc46jbn
3