[R] modify the imported version of a function

[Benjamin Tyner]

Figured it out...in case it is useful to others:

    > library(lint)

    > lint.enclos <- parent.env(asNamespace("lint"))

    > stopifnot(all(c("perl", "regex") %in% ls(lint.enclos)))

    > lint.enclos$perl
    function (pattern)
    {
        message("perl is deprecated. Please use regexp instead")
        regex(pattern)
    }
    <environment: namespace:stringr>

    > unlockBinding("perl", lint.enclos)

    > lint.enclos$perl <- lint.enclos$regex

    > lint.enclos$perl
    function (pattern, ignore_case = FALSE, multiline = FALSE, comments 
= FALSE,
        dotall = FALSE, ...)
    {
        options <- stri_opts_regex(case_insensitive = ignore_case,
            multiline = multiline, comments = comments, dotall = dotall,
            ...)
        structure(pattern, options = options, class = c("regex",
            "pattern", "character"))
    }
    <environment: namespace:stringr>



On 12/16/2016 06:06 PM, Benjamin Tyner wrote:
> Hi
>
> I saw on the assignInNamespace help page, that it changes "the copy in 
> the namespace, but not any copies already exported from the namespace, 
> in particular an object of that name in the package (if already 
> attached) and any copies already imported into other namespaces."
>
> So now I'm wondering, whether there is a way to modify such copies 
> already imported into other namespaces? For a concrete example, 
> consider the lint package (now archived on CRAN) which includes a 
> function check_pattern, which calls stringr:::perl, which has been 
> deprecated in newer versions:
>
>    > stringr:::perl
>    function (pattern)
>    {
>        message("perl is deprecated. Please use regexp instead")
>        regex(pattern)
>    }
>    <environment: namespace:stringr>
>
> so, what if I wanted to directly replace stringr:::perl with 
> stringr:::regex, in such a way that lint::check_pattern sees the 
> replacement? Is there a way, preferably without having to attach 
> stringr to the search path?
>
> (I'm mostly just interested in learning about how namespace imports 
> actually work; of course in this toy example one could use 
> suppressMessages to hide that deprecation message).
>
> Regards
> Ben