Interfaces.jl (not maintained)

NOTE: This package was initially designed as a proof of concept for interfaces in julia. However, with changes to how unions work in base julia the approach taken here no longer works.

Summary

Interfaces.jl takes a simplistic approach to defining and using interfaces in julia. Rather than creating an interface which you need to subtype for all types that satisfy the required methods, you can simply state that a type implements some interfaces without needing to modify your existing type heirarchy.

Usage

The Interface definition takes the name of the interface followed by a list of method signatures. Here define an interface called MyInterface with 2 methods func1 and func2.

@interface MyInterface begin
    func1(self::MyInterface, x::Int)
    func2(self::MyInterface, x::Float64, y::Float64)
end

Now given the following type Foo, which we may have defined ourselves or could be exposed by some third party library, but supports all of our desired methods.

type Foo
    x::Int
end
func1(self::Foo, x::Int) = return self.x + x
func2(self::Foo, x::Float64, y::Float64) = return self.x * (x + y)

We can say that Foo implements MyInterface like so.

@implements Foo <: MyInterface

or with

implements(Foo, MyInterface)

Similarly, if we want our type Foo to implement multiple Interfaces we can say.

@implements Foo <: (MyInterface, OtherInterface)

If we define a function that take MyInterface we can see that dispatching works fine if we pass in an instance of Foo

common_func(obj::MyInterface) = func1(obj, 4)

common_func(Foo(4))
# returns 8

TODO

• Improve tests to 100% coverage
• Improve input validation of method signatures