Calling a nested function from other file to a constructor

General Usage
1

let us suppose that we have:

include("file2.jl")
struct f1
    function f1():
         expressions

       function f2(a,b,c):
                return g2(a)
       end
end
end

where g2() is a nested function in a function called g1()but in another file called file2 like this:

function g1()
      function g2(b)
      return expression
      end
end

, how can i call f2i have tried this:

a=f1()
a.f2(x,y,z)

but i got an ERROR: UndefVarError: g2 not defined

2

Function g1 in file2 returns a function object. To use it you have to call g1() in your function f1 or f2

include("file2.jl")
struct f1
    function f1()
        # expressions
        ftc = g1()
        
        function f2(a,b,c)
            return ftc(a)
        end
    end
end

or

include("file2.jl")
struct f1
    function f1()
        # expressions
        function f2(a,b,c)
            ftc = g1()
            return ftc(a)
        end
    end
end

Then you can write:

a = f1() # calls the constructor returning the a callable object
a(3, 2, 1)

(Drop the colons in your function definitions :wink: In general it is easier to answer questions if you post real code instead of pseudo-code.

1 Like
3

i forgot to drop the colons because i’m coming from a Python background :sweat_smile:
but your idea is working

4

Ja, your approach looks object oriented. That made me wonder, how to define a method as an element of an object with access to other elements. Here is one way to achieve this:

mutable struct Omf
    f
    p::Int

    function Omf(p)
        omf = new()
        omf.p = p
        function fd(x)
            return omf.p * x
        end
        omf.f = fd
        return omf
    end
end

julia> omf = Omf(1)
Omf(var"#fd#3"{Omf}(Omf(#= circular reference @-2 =#)), 1)

julia> omf.f(5)
5

julia> omf.p = 2
2

julia> omf.f(5)
10

julia> omf.p = 3
3

julia> omf.f(5)
15

However, I think programming julia is fun because of multiple dispatch. Maybe you want to have a look at Stefan’s talk at JuliaCon 2019.

1 Like