> On May 24, 2016, at 4:09 PM, Timothy Bates <tim.ba...@ed.ac.uk> wrote:
>
>
> On 24 May 2016, at 12:59 am, Simon Urbanek <simon.urba...@r-project.org>
> wrote:
>> how should be determine that you want $? If it's a matrix, maybe you want [
>> ... if it's a function maybe you want ( ... it looks like a hornet's nest to
>> me, but if you provide logic, we may be able to code it up ;)
>> Cheers, Simon
>
> Hi Simon,
>
> My logic is as follows:
>
> 1. When a name is already complete, when the user pushes tab again, they are
> expecting “more” name completion, i.e., they want to access a $ or @
> sub-component.
That seems like a very strong assumption and my point questioning that
assumption. For a lot of objects $ makes no sense which is why I'm reluctant to
add $ unconditionally. Really, it only makes sense for lists (and some
subclasses) - anything else gets a bit dodgy (it works for some but not others).
That said, I suppose one possible approach would be to catch any completion
that yields just the items itself and if that happens attempt a completion with
$ appended and see what it yields. If it yields anything additional, return
that result instead. You can test whether you like that by using something like
the following:
add.fn("rcompgen.completion", function (x)
{
comp <- function(x) {
utils:::.assignLinebuffer(x)
utils:::.assignEnd(nchar(x))
utils:::.guessTokenFromLine()
utils:::.completeToken()
utils:::.CompletionEnv[["comps"]]
}
res <- unique(comp(x))
if (nzchar(x) && identical(res, x) && !identical(substr(x, nchar(x),
nchar(x) + 1L), "$")) {
rc <- comp(paste0(x, "$"))
if (!identical(substr(rc, nchar(rc), nchar(rc) + 1L), "$")) res <- rc
}
res
})
Obviously, you can eve spin that further and carry on with @ if $ doesn't work.
Cheers,
Simon
> Currently, nothing happens, and the user feels “thwarted”… like the typing
> “Simon" but then having to type a space and a tab to get "Urbanek" :-)
>
> 2. Most object components are $ indexed rather than @ indexed), so $ is the
> best guess.
>
> Based on this, a simple logic of "append $ if the current name is a valid
> name" would be an advance in many cases. I can’t see a downside.
>
> A smarter logic would call .DollarNames() on the current word and if it found
> $ items, then append the $ and display the dropdown, if not, beep.
>
> Re “why not offer mtcars[] instead of mtcars$”? or adding the round brackets
> to a function, I think the answer is that while perhaps an appropriately
> smart version of rcompgen could support this, users are expecting tab
> completion to complete names and in R, that means a complete addressable name
> for an object component.
>
> So I think that having tab add a $ accessor would seem natural, whereas
> having one tab complete the name, and the next one add brackets would not.
>
> Currently, I find that the mental context switch from completing a name to
> accessing or filling in parameters is sufficiently “different” that typing
> the bracket ending seems natural, and it’s nice that R.app gives us the
> closing bracket for free.
>
> Cheers, tim
>
> https://stat.ethz.ch/R-manual/R-devel/library/utils/html/rcompgen.html
>
> PS: Indeed, a type-aware completion system would be great (as you imply). I
> enjoy the feature in RStudio now where valid completions are given, for
> instance, within a square bracket context. i.e., mtcars[1,⇥] gives a drop
> down of column names - much easier than running names() in the terminal to
> remember what is what.
>
>
>>
>> On May 20, 2016, at 8:08 AM, Timothy Bates <tim.ba...@ed.ac.uk> wrote:
>>> Like most of us I am sure, I use the tab completion system a lot, not just
>>> to complete object names, but to pick from the drop-list created when one
>>> hits tab after a $ sign.
>>>
>>> Current situation to get to "object$part1$level2” the user currently has
>>> to type:
>>> 1. "obj→" (completed to "object")
>>> 2. Type "$→" and pick part1
>>> 3. Type "$→" and pick level2
>>>
>>> Suggestion: make a second "tab" press fill in the $-sign. That would reduce
>>> the above to:
>>> 1. "obj→" (completed to "object")
>>> 2. Type "→ →" and pick part1
>>> 3. Type "→ →" and pick level2
>>>
>>> MUCH quicker, as the dollar sign involves lifting finger off tab key,
>>> hitting (for English) shift-4 (a two hand operation, or an awkward one-hand
>>> stretch), then moving back to the tab key.
>>>
>>> Users of the @ accessor might feel left out - perhaps give them shift-tab
>>> :-)
>>>
>>> PS: Still be nice bump up the font size in the bottom tool-tip bar, if only
>>> back to the old physical height (or perhaps just re-use the RStudio
>>> tool-tip completion system)
>
>
> --
> The University of Edinburgh is a charitable body, registered in
> Scotland, with registration number SC005336.
>
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