Should glimpse() return a preview of the data only, not the lazy_dt object structure?

[edgararuiz-zz]

Providing a glimpse() into the data only would make it operate like it does in dbplyr

library(data.table)
library(dtplyr)
suppressPackageStartupMessages(library(dplyr))

glimpse(mtcars)
#> Observations: 32
#> Variables: 11
#> $ mpg  <dbl> 21.0, 21.0, 22.8, 21.4, 18.7, 18.1, 14.3, 24.4, 22.8, 19.2, 17.8…
#> $ cyl  <dbl> 6, 6, 4, 6, 8, 6, 8, 4, 4, 6, 6, 8, 8, 8, 8, 8, 8, 4, 4, 4, 4, 8…
#> $ disp <dbl> 160.0, 160.0, 108.0, 258.0, 360.0, 225.0, 360.0, 146.7, 140.8, 1…
#> $ hp   <dbl> 110, 110, 93, 110, 175, 105, 245, 62, 95, 123, 123, 180, 180, 18…
#> $ drat <dbl> 3.90, 3.90, 3.85, 3.08, 3.15, 2.76, 3.21, 3.69, 3.92, 3.92, 3.92…
#> $ wt   <dbl> 2.620, 2.875, 2.320, 3.215, 3.440, 3.460, 3.570, 3.190, 3.150, 3…
#> $ qsec <dbl> 16.46, 17.02, 18.61, 19.44, 17.02, 20.22, 15.84, 20.00, 22.90, 1…
#> $ vs   <dbl> 0, 0, 1, 1, 0, 1, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0…
#> $ am   <dbl> 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0…
#> $ gear <dbl> 4, 4, 4, 3, 3, 3, 3, 4, 4, 4, 4, 3, 3, 3, 3, 3, 3, 4, 4, 4, 3, 3…
#> $ carb <dbl> 4, 4, 1, 1, 2, 1, 4, 2, 2, 4, 4, 3, 3, 3, 4, 4, 4, 1, 2, 1, 1, 2…

d_mtcars <- as.data.table(mtcars)
dt_mtcars <- lazy_dt(d_mtcars)
glimpse(dt_mtcars)
#> List of 7
#>  $ parent       :Classes 'data.table' and 'data.frame':  32 obs. of  11 variables:
#>   ..$ mpg : num [1:32] 21 21 22.8 21.4 18.7 18.1 14.3 24.4 22.8 19.2 ...
#>   ..$ cyl : num [1:32] 6 6 4 6 8 6 8 4 4 6 ...
#>   ..$ disp: num [1:32] 160 160 108 258 360 ...
#>   ..$ hp  : num [1:32] 110 110 93 110 175 105 245 62 95 123 ...
#>   ..$ drat: num [1:32] 3.9 3.9 3.85 3.08 3.15 2.76 3.21 3.69 3.92 3.92 ...
#>   ..$ wt  : num [1:32] 2.62 2.88 2.32 3.21 3.44 ...
#>   ..$ qsec: num [1:32] 16.5 17 18.6 19.4 17 ...
#>   ..$ vs  : num [1:32] 0 0 1 1 0 1 0 1 1 1 ...
#>   ..$ am  : num [1:32] 1 1 1 0 0 0 0 0 0 0 ...
#>   ..$ gear: num [1:32] 4 4 4 3 3 3 3 4 4 4 ...
#>   ..$ carb: num [1:32] 4 4 1 1 2 1 4 2 2 4 ...
#>   ..- attr(*, ".internal.selfref")=<externalptr> 
#>  $ vars         : chr [1:11] "mpg" "cyl" "disp" "hp" ...
#>  $ groups       : chr(0) 
#>  $ implicit_copy: logi FALSE
#>  $ needs_copy   : logi FALSE
#>  $ env          :<environment: R_GlobalEnv> 
#>  $ name         : symbol _DT1
#>  - attr(*, "class")= chr [1:2] "dtplyr_step_first" "dtplyr_step"

[hadley]

Definitely!