Dependencies: What does your package need? package::function()

[Ayala Allon]

Hey all,

I apologize in advance if this is not the right forum for my question (let me know if you think I should publish this elsewhere). I'm reading the part on Dependencies: What does your package need? in Hadley's book on R packages. It says there that if I add a package dependency using import it does not mean that it will be attached along with your package, and that the best practice is to explicitly refer to external functions using the syntax package::function(). I know my question is silly but I don't understand the  package::function() part. Can someone please provide me an example of how to implement this in a code? 

Any help will be greatly appreciated,

Ayala

[Gábor Csárdi]

If you want to use the GET function from the httr package, then you can refer to it as httr::GET(...).

And of course you need to put httr in Imports in the DESCRIPTION file.

Gabor

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[Ayala Allon]

Thank you Gabor.

I have one more question concerning this issue. if I do  what you explained (and of course the put the package name in Imports in the DESCRIPTION file), it means that when one uses my package the dependencies will also be installed if he doesn't have them already and package::function() will exact the functions from the dependency right? 




Thank you again

Ayala

--

Ayala Allon, PhD Student

The Visual Working Memory Lab

The school of Psychological Sciences

Tel-Aviv University

ayala...@gmail.com

http://people.socsci.tau.ac.il/mu/royluria/

[Gábor Csárdi]

On Sun, Jul 5, 2015 at 4:49 PM, Ayala Allon <ayala...@gmail.com> wrote:

Thank you Gabor.

I have one more question concerning this issue. if I do  what you explained (and of course the put the package name in Imports in the DESCRIPTION file), it means that when one uses my package the dependencies will also be installed if he doesn't have them already

Yes.

 

and package::function() will exact the functions from the dependency right? 

I am not sure what you mean here, sorry. If `package` is installed, and it has `function`, then yes `package::function` will work.

Gabor

ps. this is really an R-help question, it has not much to do with devtools.

[Ayala Allon]

Yes this is what I meant.

Thank you again

Ayala