Hi all, In CxxWrap, there is a check to determine if a function declaration should be prepended with the module, for example to extend functions in Base, using isdefined. However, when creating functions that have the same name as a function in Base without the intention to add methods to Base, thi…

[image] barche: Is it allowed to have a function that is named the same as a function in Base, but not extending it? Yes, there’s nothing special about Base. [image] barche: or define the function so that this error is not triggered? Just define it?

[image] yuyichao: Just define it? Right. That works, except if you define it in an included file. See also this related question Trying not to overload Base.open - #4 by Sukera , where @Sukera demonstrated how you can trigger this by “just defining it”. This is the case here: CxxWrap builds t…

It’s not very clear to me what’s the requirement here. What’s the difference between what you need and importing from a normal module?

In another word, There’s nothing special about included file. The error you get in Trying not to overload Base.open - #2 by Sukera is entirely expected and there’s no way around it. You should not change the behavior based on if something has been used or not to avoid the error. This error has to …

Right. There’s nothing special about the included file. As far as I understand the problem is that isdefined(mymodule, open) returns true, even if I never explicitly import Base: open in mymodule. In that case, the code in CxxWrap returns the name of the function and exports it to the module, but i…

[image] jstrube: In that case, the code in CxxWrap returns the name of the function and exports it to the module, but it gets attached to Base . No. IIUC, you are talking about the case where you have open(...) = ..., this will never create anything attached to Base without an explicit import.…

[image] yuyichao: No. IIUC, you are talking about the case where you have open(...) = ... , this will never create anything attached to Base without an explicit import . Please take a look at the second example in the OP. The very call of isdefined causes the Base.open error without Base.open…

[image] jstrube: Please take a look at the second example in the OP. The very call of isdefined causes the Base.open error without Base.open being imported or called directly anywhere. Right, what I said about “just define it” means not using isdefined. Also, the error doesn’t contradict what…

And just to be clear. I’m not talking about how you can use CxxWrap. I’ve never used it and I don’t know how it is intended to work. Instead, I’m talking about how it has to work and what kind of semantics it should not aim to provide.

[image] jstrube: where @Sukera demonstrated how you can trigger this by “just defining it”. You might have misunderstood the code snippet I posted in the other thread - I was not defining a new addition to Base.open in there, merely using the definition exported from Base. Since that brings t…

Using isdefined to check where a function is defined

General Usage

yuyichao April 14, 2020, 3:17pm 17

Yes, that’s what you are doing if you were writing Julia code.

1 Like

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Using isdefined to check where a function is defined

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