[Rd] Best way to implement optional functions?

[ProfJCNash]

I'm relieved to read that this issue is becoming more visible. In my own
work on optimizers, I've been finding it awkward to provide a clean
solution to allowing users to run e.g., optimx, when some optimizers are
not installed. Unfortunately, I've not found what I consider to be a
solution with any elegance.

JN

On 15-10-23 06:00 AM, r-devel-request at r-project.org wrote:
> Message: 8
> Date: Thu, 22 Oct 2015 15:55:01 -0400
> From: Duncan Murdoch <murdoch.duncan at gmail.com>
> To: "R-devel at r-project.org" <r-devel at r-project.org>
> Subject: [Rd] Best way to implement optional functions?
> Message-ID: <56293F15.80509 at gmail.com>
> Content-Type: text/plain; charset=utf-8; format=flowed
> 
> I'm planning on adding some new WebGL functionality to the rgl package, 
> but it will pull in a very large number of dependencies. Since many 
> people won't need it, I'd like to make the new parts optional.
> 
> The general idea I'm thinking of is to put the new stuff into a separate 
> package, and have rgl "Suggest" it.  But I'm not sure whether these 
> functions  should only be available in the new package (so users would 
> have to attach it to use them), or whether they should be in rgl, but 
> fail if the new package is not available for loading.
> 
> Can people suggest other packages that solve this kind of problem in a 
> good way?
> 
> Duncan Murdoch