I have two files. The first includes the second. The compiler complains about the variable var not being defined in the second file. Why? First file: function a() var = 1; include("b.jl") end a() Second file: @show var When I run include("a.jl") I get: ERROR: LoadError: LoadError: UndefVarEr…

[image] Is "include" safe to use inside a function? General Usage Is the following safe to do? #testinclude.jl a = 2 julia> function f() include("testinclude.jl") return a end f (generic function with 1 method) julia> f() 2 It has a mac…

Because things are evaluated into global scope (where there is no var).

I’m not sure I follow. I thought that the compiler would simply slurp the contents of the included file. Evaluation of include("a.jl") goes through without a hitch. But then when I run, there is the error. I find that confusing. I thought the embedded file b.jl would simply become part of the code…

https://docs.julialang.org/en/v1/base/base/#Base.include Evaluate the contents of the input source file in the global scope Include is just another function. You’re not running it by defining the function.

I think I’m beginning to see the light. The compiler doesn’t actually copy the contents of the included file into the function, but does this: julia> @code_lowered a() CodeInfo( 1 ─ …

[image] PetrKryslUCSD: I thought that the compiler would simply slurp the contents of the included file. What can I say, that was a wrong assumption. It parses it and evaluates the expression (and evals go into the current global scope unless given another module).

So is there any way I could get that behavior: I am motivated by having a piece of code that I would like to incorporate into multiple pieces “by inclusion” instead of by defining a function and calling that function? I suppose I am looking for a macro?

Good find. No mystery after all :slight_smile: Thanks.

This misconception probably isn’t entirely your doing. Folks (maybe including myself?) have often talked about include as a “copy-pasting” of code when discouraging others from trying to use it as a pseudo-packaging mechanism. It may be worth trying to steer away from that mental model.

Indeed, you’re right. That’s the soundbite I remembered.

I must confess to being tripped up by misunderstanding exactly what include does. Indeed, I think it is a common misconception. I can’t help but feel that it is partly due to the name include which might be associated with pre-processor directives in other languages. And it is commonly used for the…

Include mystery

General Usage

kristoffer.carlsson March 26, 2019, 4:33pm 8

It has a macro for this.

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Include mystery

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