Can Methods Be Created Dynamically in Go?

Creating Methods Dynamically in Go

It is possible to dynamically create functions in Go using reflect.MakeFunc, but what about creating methods (functions with receivers)?

No Direct Way to Create Methods at Runtime

Unlike functions, it is not possible to create methods dynamically in Go. This is because the receiver's type's method set remains static at compile time. If it were possible to add or remove methods from a type at runtime, interface type-checking would require runtime checks on every function call, significantly impacting performance.

Technical Hack for Creating Method-Like Values

Although a direct runtime method creation is not possible, a hack involves forking the reflect package to create a value representing a method attached to an arbitrary type. However, this method will not change the actual method set of the type.

Exchanging Method Pointers on an Object

Another approach is to modify the vtable of a non-empty interface value. In Go, interface values hold a pointer to the underlying concrete type's vtable, a table of method pointers. By obtaining a non-empty interface value and modifying its vtable, one can effectively exchange method pointers on an object.

However, this technique is not recommended due to its complex implementation and potential consequences.

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