How to add a new module?

[phma]

I created a directory ~/src/juliapractice (all the code I write is in ~/src) and used Pkg to create a project. I then added a file and tried to load it. The files look like this:
Project.toml:

[code]authors = [“phma ”]
name = “juliapractice”
uuid = “a24d6352-b19b-11e8-179c-1589c5648784”
version = “0.1.0”

[deps][/code]
src/juliapractice.jl:

[code]module juliapractice

greet() = print(“Hello World!”)

end # module[/code]
mandelbrot.jl:

[code]module mandelbrot

function julia_set(z, c)
n = 0
while abs2(z) < 4
z = z^2 + c
n += 1
end
n
end

end[/code]
Running julia in the juliapractice directory, I did this:

[code] (v1.0) pkg> activate .

julia> import mandelbrot
ERROR: ArgumentError: Package mandelbrot not found in current path:

• Run Pkg.add("mandelbrot") to install the mandelbrot package.

Stacktrace:
[1] require(::Module, ::Symbol) at ./loading.jl:817

julia> import juliapractice
[ Info: Precompiling juliapractice [a24d6352-b19b-11e8-179c-1589c5648784]

julia> julia_set(0,0.5)
ERROR: UndefVarError: julia_set not defined
Stacktrace:
[1] top-level scope at none:0

julia> greet()
ERROR: UndefVarError: greet not defined
Stacktrace:
[1] top-level scope at none:0

julia> juliapractice.julia_set(0,0.5)
ERROR: UndefVarError: julia_set not defined
Stacktrace:
[1] getproperty(::Module, ::Symbol) at ./sysimg.jl:13
[2] top-level scope at none:0

julia> juliapractice.greet()
Hello World!
julia>[/code]
How do I tell Julia about the new file?

[Tamas_Papp]

please quote your code

PSA: how to quote code with backticks

This is a short post on using backticks (` and ```) to quote code, with the intention of benefiting users who are confused by this feature of the site. The intention is to make it linkable when necessary. Why By quoting your code, you get a monospaced font (which preserves indentation) and syntax highlighting. This helps people who read your code and want to help you. Displayed code looks like this: function displayed_code(x::Int, y::Int) if x < y println("x is smaller") else …

[rdeits]

Julia is expecting your juliapractice package to just define the juliapractice module, so having a second mandelbrot module at the top level of that file won’t work. You can define multiple modules at the same time, but they need to be nested inside the top-level module for the package. So this is ok:

module juliapractice

module SubModule1
  greet() = println("hello 1")
end

module SubModule2
  foo() = 5
end
end

The rest of the issues you’re seeing are just the normal way that import works in Julia: when you import Foo you need to do Foo.bar(). See: Modules · The Julia Language

[phma]

Trying again to post the files:
Project.toml:

authors = ["phma <snip>"]
name = "juliapractice"
uuid = "a24d6352-b19b-11e8-179c-1589c5648784"
version = "0.1.0"

[deps]

juliapractice.jl:

module juliapractice

greet() = print("Hello World!")

end # module

mandelbrot.jl:

module mandelbrot

function julia_set(z, c)
    n = 0
    while abs2(z) < 4
        z = z^2 + c
        n += 1
    end
    n
end

end

If mandelbrot.jl should go in the juliapractice module, how do I tell Julia to compile both files together?

[fredrikekre]

You put include("mandelbrot.jl") somewhere inside the juliapractice module.

[jling]

Also, try to use Pkg.generate instead of manually creating and tracing Project.toml
More here.