Add subclasses

[krlmlr]

We want to know that a formattable is actually "accounting" or "currency" after we have constructed it. This helps implementing pillar_shaft() methods for formattable.

Are you on board with this? Are there reasons against? I ran a revdepcheck: https://github.com/renkun-ken/formattable/actions/runs/660611546. Two packages are now failing but it's unrelated to this PR because we no longer import htmltools and rmarkdown.

This is a big change I couldn't break into smaller pieces.

[renkun-ken]

I'll take a closer look at this soon.

[renkun-ken]

Is there a reason prefix and suffix uses a class? These two functions are intended to tweak existing formats.

I inspect the class attribute like the following:

> str(suffix(prefix(currency(acct, symbol = "HK$"), "*"), "#"))                                                                                                                                                                                                                                                                          
 'formattable_accounting' num [1:3] *HK$10,000.00# *HK$500,000.00# *HK$-20,000.00#
 - attr(*, "formattable")=List of 5
  ..$ formatter: chr "formatC"
  ..$ format   :List of 3
  .. ..$ format  : chr "f"
  .. ..$ big.mark: chr ","
  .. ..$ digits  : int 2
  ..$ preproc  : NULL
  ..$ postproc :List of 3
  .. ..$ :function (str, x)  
  .. ..$ :function (str, x)  
  .. ..$ :function (str, x)  
  ..$ class    : chr [1:4] "formattable_suffix" "formattable_accounting" "formattable" "numeric"

However, the prefix class seems missing somehow?

[krlmlr]

Good point, this doesn't look right. Maybe prefix and suffix don't need their own class.

[renkun-ken]

A bit off the topic. @krlmlr Please feel free to add yourself as a contributor to DESCRIPTION to reflect your active participation of the package. Thanks!

[krlmlr]

pillar 1.6.0 is on CRAN now.

[renkun-ken]

One thing to notice is that the class name is bit too long for printing:

> library(formattable)
> library(data.table)
> library(tibble)

> p <- data.frame( 
    id = c(1, 2, 3, 4, 5), 
    name = c("A1", "A2", "B1", "B2", "C1"), 
    balance = accounting(c(52500, 36150, 25000, 18300, 7600), format = "d"), 
    growth = percent(c(0.3, 0.3, 0.1, 0.15, 0.15), format = "d"), 
    ready = formattable(c(TRUE, TRUE, FALSE, FALSE, TRUE), "yes", "no"))                                                                                                                                                                                                                              

> p                                                                                                                                                                                                                                                                                                   
  id name balance growth ready
1  1   A1  52,500    30%   yes
2  2   A2  36,150    30%   yes
3  3   B1  25,000    10%    no
4  4   B2  18,300    15%    no
5  5   C1   7,600    15%   yes

> as_tibble(p)                                                                                                                                                                                                                                                                                        
# A tibble: 5 x 5
     id name  balance    growth     ready     
  <dbl> <chr> <frmttbl_> <frmttbl_> <frmttbl_>
1     1 A1    52,500      30%       TRUE      
2     2 A2    36,150      30%       TRUE      
3     3 B1    25,000      10%       FALSE     
4     4 B2    18,300      15%       FALSE     
5     5 C1    7,600       15%       TRUE      

> as.data.table(p)                                                                                                                                                                                                                                                                                    
      id   name                  balance                growth                 ready
   <num> <char> <formattable_accounting> <formattable_percent> <formattable_logical>
1:     1     A1                   52,500                   30%                   yes
2:     2     A2                   36,150                   30%                   yes
3:     3     B1                   25,000                   10%                    no
4:     4     B2                   18,300                   15%                    no
5:     5     C1                    7,600                   15%                   yes

Do you think we should simplify or shorten the class name?

[krlmlr]

We could also add pillar_shaft() and type_sum() methods, perhaps as a separate PR?

[renkun-ken]

We could also add pillar_shaft() and type_sum() methods, perhaps as a separate PR?

A separate PR makes good sense.