dot-split_if_language function

Split contrast function using parens

If something like set_contrasts(df, var ~ sum_code()) then what's extracted from the formula isn't the symbol for the function sum_code but a language object. This can be converted to a list to extract the function symbol and then any arguments provided in the parens. The latter needs to be evaluated in the original environment, for example if set_contrasts(df, var ~ sum_code(scores=c(.1,.5,.6)) is called, the scores list would not evaluate the c(...) call, yielding an error that the scores argument isn't the right length (because it would be length 1, not 3).

.split_if_language(params, var_envir)

Arguments

• params: Parameters extracted from formula parsing
• var_envir: Environment to evaluate expressions in

Returns

Parameter list with code_by set to the correct symbol & an additional list entry for other arguments, which will be empty if no arguments are provided.