[Rd] Fields used by available.packages

[Kurt Hornik]

>>>>> Lluís Revilla writes:

Lluis,

So in available.packages() I could replace

    if (is.null(fields))
	fields <- requiredFields
    else {
	stopifnot(is.character(fields))
	fields <- unique(c(requiredFields, fields))
    }

by someting like

    if(is.null(fields))
        fields <- getOption("available_packages_fields")
    if(is.null(fields))
        fields <- requiredFields
    else {
	stopifnot(is.character(fields))
	fields <- unique(c(requiredFields, fields))
    }

?

Best
-k



> Hi all,
> I have recently been researching how available.packages and
> install.packages filter packages from repositories with additional fields
> in their PACKAGES file.

> Currently there are some default filters, but users (and R admins) can set
> up their own filters by passing a list to the fields argument or adding
> them to the "available_packages_filters" option.
> But if the fields used by the filters are not read by default, then users
> must manually add the required fields to each call to available.packages.

> This makes it difficult to use new fields and to control what is installed
> in highly regulated systems which want to use more fields to select what is
> installed.

> Current workarounds considered are:
>  1) The filtering function requiring new fields intercepts the call to
> available.packages and adds the desired fields via eval in
> parent.environment and then adds the filters again.
>  2) Import new data (remote or local) when filtering packages, merge them
> and filter accordingly.
>  3) Suggestions?

> The first solution is complicated, while the second doesn't use the R
> machinery of tools::write_PACKAGES to set up the repository with all the
> fields (although how to add more fields to the repository file is a
> different issue).

> Would it be possible to add a new option to add fields to be read by
> available.packages, similar to filters?
> The same approach for fields as for filters would avoid the two workarounds
> mentioned. To match it, the new option could be named
> "available_packages_fields".

> I look forward to hearing from you,

> Lluís

> 	[[alternative HTML version deleted]]

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