unconf17
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ropensci
Extensions to R / RStudio's autocompletion system
It would be handy to allow packages to register their own autocompletion routines for certain functions. A simple example might be shiny::runExample() -- users might write
shiny::runExample(<TAB>)
The autocompletion system could then provide the set of available examples as autocompletion candidates.
Definitely think this could be useful, I experimented a little with this for base R's completion at https://github.com/tidyverse/readxl/pull/320/files.
People completions independently won't work well because you can only define one custom completion function at a time. But a completion package package authors can use to register completion functions and will handle the fallbacks for you will work well.
We also need a way to hook into RStudio's completion machinery and provide helper functions to make registration of completion functions easier.
Ideally we'd have some way to take advantage of the file autocomplete, but with some function that filter the list of files.
Here's the infrastructure I'm imagining:
We could develop an R package (call it autocomp or something similar), and it would be responsible for maintaining a set of autocompletion functions, as registered by other users / packages.
Suppose we wanted to register an autocompleter for shiny::runExample(). We could do this with an interface like:
# imagine this living in a package's .onLoad or similar
autocomp::register_completer("shiny::runExample", "example", function(token) {
examples <- list.files(system.file("examples", package = "shiny"))
types <- rep(autocomp::completion_types$FILE, length(examples))
autocomp::completions(examples, types)
})
The first argument is used to define the package + function name; the second the argument for which this completer should be registered, the third the actual completion function (which should return a set of completion results).
The 'token' object would simply be the R code lying before the user's cursor; we can think about what other context might need to be stuffed in there.
The R package could register its top-level own custom completer (ie, by defining rc.options("custom.completer"), to ensure that registered completers work in plain-old R sessions, while hosting environments (e.g. RStudio) could do its own work to override + use an autocomp-registered completion engine.
Application numero uno: autocompleting username/repo in install_github() from some reasonable set of options.
Jenny, just use https://github.com/jimhester/autoinst :stuck_out_tongue_winking_eye:
@jimhester it must be magical if it knows what I am about to install from GitHub. :)
Well the lookup has to error first, but it uses http://rpkg.gepuro.net/ to figure out GitHub packages, which is clearly not perfect, but it works pretty well.
Check my comment on https://github.com/ropensci/unconf18/issues/65#issuecomment-723088752
Keeping this in case anyone is interested in this matter.
Just a prototype which is doing following things
- It can auto-complete
future::plan - dplyr::filter unique cases (like
iris %>% filter(Species == <TAB>)) - match.arg type arguments in user defined or any functions (like
cor(method = <TAB>))
It can be extended to any custom packages/ functions I guess.
