CODEWITHSUNDEEP
julia
user2329125
user2329125

Reputation:

How can you use functions from outside a module inside a module

Basically I want a module that can use functions that are outside its scope. I need this because my work will only provide a framework where the user will be able to put its own code in. Something like this

Simulation.jl

abstract AbstractType

function startSimulation(unknown::AbstractType)
    doStuff(unknown)
end

MyModule.jl

module MyModule
    include("Simulation.jl")
    export AbstractType, startSimulation
end

SomeImplementation.jl

type ConcreteType <: AbstractType
    variable::Int64
end

doStuff(me::ConcreteType)
    me.variable
end

and finally Main.jl

# push!(LOAD_PATH, pwd()) # for local usage
using MyModule
include("SomeImplementation.jl")
startSimulation(ConcreteType(5))

Where Simulation.jl and MyModule.jl are written by me and SomeImplementation.jl and Main.jl are written by the user.

Now the above example does not work, because modules have their own namespace and even tho SomeImplementation.jl is imported in main at line 3, the interpreter will not see it in line 4 of Simulation.jl.

I can not import anything in MyModule.jl, because I can not know how the user will name his stuff or what extra libs he might even need.

Is there are way to do this with modules? Otherwise I will just not use modules.

Upvotes: 5

Views: 1065

Answers (1)

mbauman
mbauman

Reputation: 31342

The answer here is to create stubs for all the functions you want to call within MyModule as a required interface for the custom subtypes of AbstractType. That is, within MyModule, you'd have:

abstract AbstractType

doStuff(::AbstractType) = error("custom AbstractType objects must define a `doStuff` method)

function startSimulation(unknown::AbstractType)
    doStuff(unknown)
end

Then the concrete implementations just need to specifically add their doStuff method to the function in MyModule by importing it or qualifying it:

MyModule.doStuff(me::ConcreteType)
    me.variable
end

Upvotes: 10

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