# "contour not defined" when using my package

**URL:** <https://discourse.julialang.org/t/contour-not-defined-when-using-my-package/52727>\
**Category:** General Usage\
**Tags:** package\
**Created:** [January 2, 2021, 5:37am UTC](https://discourse.julialang.org/t/contour-not-defined-when-using-my-package/52727 "2021-01-02T05:37:39Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![EmadMasroor](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/emadmasroor/32/7527_2.png) [@EmadMasroor](https://discourse.julialang.org/u/EmadMasroor)\
**Post date:** [January 2, 2021, 5:37am UTC](https://discourse.julialang.org/t/contour-not-defined-when-using-my-package/52727/1 "2021-01-02T05:37:39Z")

</div>

Hello,

I am building a new package for the first time, and I’m running into a problem when I call one of the functions exported by my package, [SimpleNavierStokes.jl](https://github.com/Emadmasroor/SimpleNavierStokes.jl).

The package exports a function, `LidDrivenCavity()`. This function returns an object of type `Results`, which I have defined inside the `SimpleNavierStokes` module like this:

```julia
struct Results
    ψ::Array
    ω::Array
    hist::Array
    x::Array
    y::Array
    ...
end

```

This works as expected. Next, I have defined a custom “plotting function”. Rather than redefining `plot()` with my new type `Results`, I decided to define my own function, which does something like this:

```julia
ShowStreamlines(sol::Results) = contour(sol.x,sol.y,sol.ψ)

```

(I have also tried replacing `sol::Results` with `sol:SimpleNavierStokes.Results`; this doesn’t appear to help.) Aside: I know this looks like a trivial function, but I plan to make it more useful and so I would like to do something like this rather than expecting the user to call `plot` on the different constituent parts of `Results`.

This function does get exported, but when I call it on an object of type `Results`, like this:

```julia
Pkg.add("https://github.com/emadmasroor/SimpleNavierStokes.jl")
using Plots, SimpleNavierStokes
a = LidDrivenCavity()
ShowStreamlines(a)

```

I get:

```julia
ERROR: UndefVarError: contour not defined
Stacktrace:
 [1] ShowStreamlines(::Results) at /home/emad/.julia/packages/SimpleNavierStokes/JTjDG/src/plot_utils.jl:12
 [2] top-level scope at REPL[26]:1

```

Just to be clear, my REPL does recognize the function `contour`, because immediately after the above, if I type:

```julia
contour

```

I get the expected: `contour (generic function with 1 method)`.

Why does this happen, and how can I fix it? I don’t think I should have to put a `using Plots` inside my own package, other packages don’t really do this. But why does my code not recognize `contour`, when my current environment contains `Plots` and the functions are immediately available?

Note: If I subsequently define a function like `ShowStreamlines` inside the REPL, say by doing this at the REPL

```julia
Show2(sol::SimpleNavierStokes.Results) = contour(sol.x,sol.y,sol.ψ)
Show2(a)

```

it works as expected, and I get the output of the contour plot. So I am probably doing something wrong inside my package.

I appreciate any help!

---

<div class="post-metadata">

**Author:** ![affans](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/affans/32/11911_2.png) [@affans](https://discourse.julialang.org/u/affans)\
**Post date:** [January 2, 2021, 6:51am UTC](https://discourse.julialang.org/t/contour-not-defined-when-using-my-package/52727/2 "2021-01-02T06:51:32Z")

</div>

> [@EmadMasroor](#):
>
> Why does this happen, and how can I fix it? I don’t think I should have to put a `using Plots` inside my own package, other packages don’t really do this.

Some one can correct me, but I think you need to either have the `Plots` dependency (i.e. `using Plots`) or import it directly if you want to eventually overload it. Right now, your `Module` dosn’t know about the function `contour` since you havn’t defined or imported the method anywhere within the scope of your module. Ask yourself, is `SimpleNavierStokes.contour()` defined anywhere?

The reason it works in the REPL is because the REPL module scope is `Main` and you are indeed bringing in the `contour` function by `using Plots`.

---

<div class="post-metadata">

**Author:** ![EmadMasroor](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/emadmasroor/32/7527_2.png) [@EmadMasroor](https://discourse.julialang.org/u/EmadMasroor)\
**Post date:** [January 2, 2021, 8:22am UTC](https://discourse.julialang.org/t/contour-not-defined-when-using-my-package/52727/3 "2021-01-02T08:22:39Z")

</div>

Okay, this explanation makes sense - I’ll add `using Plots` inside my module, then. I guess I was expecting that, when a function like `ShowStreamlines` is called, the scope from which you call it would also be seen by the code inside that function. But it makes sense that this is not the case.

Thanks for your help!