Allow scores in polynomial contrasts about contrastable HOT 4 CLOSED

Note that adding manual scores functionality would also require a change to the function that checks whether a contrast matrix was derived from contr.poly. So, that function would need the scores argument passed to it as well.

from contrastable.

Functionality for allowing empty parentheses in the formula syntax and additional arguments is available on the parens branch. Will be merged once I write more documentation. In general though, for a four level factor var in df:

enlist_contrasts(df, var ~ contr.poly)
enlist_contrasts(df, var ~ contr.poly())

Are now equivalent, eliminating the need to remove the () when using tab-autocomplete.

# assuming level names 1, 2, 3, 4
enlist_contrasts(df, var ~ scaled_sum_code)
enlist_contrasts(df, var ~ scaled_sum_code())
enlist_contrasts(df, var ~ scaled_sum_code + 1)
enlist_contrasts(df, var ~ scaled_sum_code() + 1)

Are also all equivalent.

my_scores <- c(.1, .2, .5, .7)
enlist_contrasts(df, var ~ contr.poly(scores = c(.1, .2, .5, .7)))
enlist_contrasts(df, var ~ contr.poly(c(.1, .2, .5, .7)))
enlist_contrasts(df, var ~ contr.poly(scores = my_scores))
enlist_contrasts(df, var ~ contr.poly(my_scores))

Are all equivalent, importantly allowing for scores to be manually specified by the user when using orthogonal polynomials. Note that the 2nd and 4th ones, which don't specify the argument name, only work because scores is the second positional argument (after n, which is auto-filled). I would recommend specifying the argument name though.

Errors:

enlist_contrasts(df, var ~ contr.poly(4)) will throw an error because the n argument is automatically supplied through the package's functionality, so specifying 4 will be set to the next positional argument, here scores.

enlist_contrasts(df, var ~ contr.poly(n=4)) will throw an error because n is specified twice (again because the package does it automatically). A more helpful error message will be written for this later.

enlist_contrasts(dv, var ~ contr.poly(bogus = 5)) will throw an error because bogus is an unused argument for contr.poly

glimpse_contrasts remains unchanged for the time being, and will likely become a separate enhancement issue.

from contrastable.

Not really an update but putting the current error messages for each example here for future reference when I update the errors:

enlist_contrasts(mtcars, gear ~ contr.poly(4))
Converting to factors: gear
Error in (function (n, scores = 1:n, contrasts = TRUE, sparse = FALSE)  : 
  'scores' argument is of the wrong length

Should make clear that n should not be specified in contrast-setting functions

enlist_contrasts(mtcars, gear ~ contr.poly(n=4))
Converting to factors: gear
Error in (function (n, scores = 1:n, contrasts = TRUE, sparse = FALSE)  : 
  formal argument "n" matched by multiple actual arguments

Should make clear that n should not be specified in contrast-setting functions

enlist_contrasts(mtcars, gear ~ contr.poly(bogus=4))
Converting to factors: gear
Error in (function (n, scores = 1:n, contrasts = TRUE, sparse = FALSE)  : 
  unused argument (bogus = 4)

actually this one can stay as is I think

# Gear has 3 levels
enlist_contrasts(mtcars, gear ~ contr.poly(scores = 2))
Converting to factors: gear
Error in (function (n, scores = 1:n, contrasts = TRUE, sparse = FALSE)  : 
  'scores' argument is of the wrong length

enlist_contrasts(mtcars, gear ~ contr.poly(scores = 1:2))
Converting to factors: gear
Error in (function (n, scores = 1:n, contrasts = TRUE, sparse = FALSE)  : 
  'scores' argument is of the wrong length

The fix is in the scores = 1:n part, but this can perhaps be made more clear by adding "length of scores should equal {length(levels(df$var))}"

from contrastable.

With some recent additions, namely to how functions and calls are handled, some of these aren't issues anymore. Really only this one is confusing/concerning:

enlist_contrasts(mtcars, gear ~ contr.poly(n=4))
Converting to factors: gear
Error in (function (n, scores = 1:n, contrasts = TRUE, sparse = FALSE)  : 
  formal argument "n" matched by multiple actual arguments

This should be addressed in .bundle_params. I'll fix this right now. The behavior here will be that n is replaced by the actual number of levels with a warning that this is happening. The situation this could occur in is if your analysis has a factor with 4 levels, then you filter a portion out and set the column to a factor not realizing you removed a level, leaving you with 3. If you have a set_contrasts later on that already has varName ~ foo(n=4) then we'll run into the situation here.

from contrastable.