How to check if an object has a particular method?

Question

In Go, how do you check if an object responds to a method?

For example, in Objective-C this can be achieved by doing:

if ([obj respondsToSelector:@selector(methodName:)]) { // if method exists   [obj methodName:42]; // call the method } 

Answer 1

A simple option is to declare an interface with just the method you want to check for and then do a type assert against your type like;

 i, ok := myInstance.(InterfaceImplementingThatOneMethodIcareAbout)  // inline iface declaration example  i, ok = myInstance.(interface{F()}) 

You likely want to use the reflect package if you plan to do anything too crazy with your type; http://golang.org/pkg/reflect

st := reflect.TypeOf(myInstance) m, ok := st.MethodByName("F") if !ok {     // method doesn't exist } else {     // do something like invoke m.F }