[Rd] declare and validate options

[Duncan Murdoch]

On 29/03/2024 11:59 a.m., Antoine Fabri wrote:
>     I think there are too many packages that would need changes under this
>     scheme.
> 
> 
> There would be zero if the registration of options is not required for 
> packages first uploaded on CRAN before the feature is implemented.
> If an option is not registered no validation is triggered and nothing 
> breaks even if we opt in the behavior.

Sorry, I missed that.  Then the objection is that this would require 
CRAN to apply two different sets of rules on submissions. When a 
resubmission arrived, they'd need to look in the archive to find out 
which set of rules applied to it.  They do a bit of that now 
(determining if a submission is a resubmission, for example), but this 
would be a bigger change.  I don't think date of first submission is 
ever currently used.

>     If those functions could be made simple enough and bulletproof and were
>     widely adopted, maybe they'd be copied into one of the base packages,
> 
> Sure but realistically few maintainers will opt-in for more restrictions.

If this is something that you want CRAN to force on package authors, 
then you need to give some hard evidence that it will fix things that 
cause trouble.  But if you only apply the rule to new packages, not 
updates to old ones, it's hard to believe that it will really make much 
difference, though it will still be extra work for CRAN and R Core.

> if posit did something on those lines maybe it would have a chance but 
> otherwise I don't see an optional feature like this spread very far.
> Or we need this package to make working with options really really much 
> easier for themselves as developers, not just beneficial for users in 
> the long run.

That should be a goal regardless of who does it.

Think about the development of the pipe operator:  it was in magrittr 
(and I think another package, but I forget the name) first, was widely 
adopted, then a simpler version was brought into base R.

Duncan Murdoch


> 
> Le ven. 29 mars 2024 à 16:25, Duncan Murdoch <murdoch.duncan using gmail.com 
> <mailto:murdoch.duncan using gmail.com>> a écrit :
> 
>     On 29/03/2024 10:52 a.m., Antoine Fabri wrote:
>      > Dear r-devel,
>      >
>      > options() are basically global variables and they come with
>     several issues:
>      > * they're not really truly owned by a package aside from loose naming
>      > conventions
>      > * they're not validated
>      > * their documentation is not standard, and they're often not
>     documented at
>      > all, it's hard to know what options exist
>      > * in practice they're sometimes used for internal purposes, which
>     is at
>      > odds with their global nature and contribute to the mess, I think
>     they can
>      > almost always be replaced by objects under a `globals`
>     environment in the
>      > namespace, it's just a bit more work
>      >
>      > I tried to do as much as possible with static analysis using my
>     package opt
>      > but it can only go so far :
>     https://github.com/moodymudskipper/opt
>     <https://github.com/moodymudskipper/opt>
>      >
>      > I think we can do a bit better and that it's not necessarily so
>     complex,
>      > here's a draft of possible design :
>      >
>      > We could have something like this in a package to register
>     options along
>      > with an optional validator, triggered on `options(..)` (or a new
>     function).
>      >
>      > # similar to registerS3method() :
>      > registerOption("mypkg.my_option1")
>      > registerOption("mypkg.my_option2", function(x)
>     stopifnot(is.numeric(x))
>      > # maybe a `default` arg too to avoid the .onLoad() gymnastics and
>     invisible
>      > NULL options
>      >
>      > * validation is a breaking change so we'd have an environment
>     variable to
>      > opt in
>      > * validation occurs when an option is set AND the namespace is
>     already
>      > loaded (so we can still set options without loading a namespace)
>     OR it
>      > occurs later when an applicable namespace is loaded
>      > * if we register an option that has already been registered by
>     another
>      > package, we get a message, the validator of the last loaded
>     namespace is
>      > used, in practice due to naming conventions it doesn't really
>     happen, CRAN
>      > could also enforce naming conventions for new packages
>      > * New packages must use registerOption() if they define options,
>     and there
>      > must be a standard documentation page for those, separately or
>     together
>      > (with aliases), accessible with `?mypkg.my_option1` etc...
>      >
>      > This could certainly be done in different ways and I'd love to
>     hear about
>      > other ideas or obstacles to improvements in this area.
>      >
> 
>     I think there are too many packages that would need changes under this
>     scheme.
> 
>     A more easily achievable improvement would be to provide functions to
>     support registration, validation and documentation, and leave it up to
>     the package author to call those.  This wouldn't give you validation at
>     the time a user set an option, but could make it easier to validate
>     when
>     the package retrieved the value:  specify rules in one place, then
>     retrieve from multiple places, without needing to duplicate the rules.
> 
>     If those functions could be made simple enough and bulletproof and were
>     widely adopted, maybe they'd be copied into one of the base packages,
>     but really the only need for that would be to support validation on
>     setting, rather than validation on retrieval.
> 
>     Duncan Murdoch
>