Tidy dots in bind_rows(), bind_cols() and combine()

[krlmlr]

to resolve ambiguity when these functions are used with just one argument, see #3387 (comment):

library(tidyverse)
combine(list(1))
#> [1] 1
combine(list(1), list(2))
#> [[1]]
#> [1] 1
#> 
#> [[2]]
#> [1] 2

Created on 2018-03-12 by the reprex package (v0.2.0).

The first call should also return a list, if unpacking is desired, the user can use combine(!!!list(1)) (which currently doesn't work).

Implement new verbs, or support a compatibility argument via pkgconfig.

[hadley]

I don't think this is tidy evaluation so much as tidy dots.

[romainfrancois]

bind_rows handles tidy dots already:

library(tidyverse)

datas <- map( 1:3, ~tibble(x = seq_len(.)))
bind_rows(!!!datas)
#> # A tibble: 6 x 1
#>       x
#>   <int>
#> 1     1
#> 2     1
#> 3     2
#> 4     1
#> 5     2
#> 6     3
bind_rows(!!!datas, tibble(x = 5))
#> # A tibble: 7 x 1
#>       x
#>   <dbl>
#> 1     1
#> 2     1
#> 3     2
#> 4     1
#> 5     2
#> 6     3
#> 7     5

So does bind_cols:

library(tidyverse)

datas <- map( c("a", "b", "c"), ~tibble( !!. := 1:10))
bind_cols(!!!datas)
#> # A tibble: 10 x 3
#>        a     b     c
#>    <int> <int> <int>
#>  1     1     1     1
#>  2     2     2     2
#>  3     3     3     3
#>  4     4     4     4
#>  5     5     5     5
#>  6     6     6     6
#>  7     7     7     7
#>  8     8     8     8
#>  9     9     9     9
#> 10    10    10    10
bind_cols(!!!datas, tibble(d = 1:10))
#> # A tibble: 10 x 4
#>        a     b     c     d
#>    <int> <int> <int> <int>
#>  1     1     1     1     1
#>  2     2     2     2     2
#>  3     3     3     3     3
#>  4     4     4     4     4
#>  5     5     5     5     5
#>  6     6     6     6     6
#>  7     7     7     7     7
#>  8     8     8     8     8
#>  9     9     9     9     9
#> 10    10    10    10    10

[hadley]

So this is more about disabling existing behaviour than adding new behaviour?

[krlmlr]

Yes, the first expression in the reprex should return a list. I commented in the PR.