more changes for non-standard arguments for #315

Author: topepo

NEWS.md

@@ -4,6 +4,12 @@
 
  * `tidyr` >= 1.0.0 is now required. 
 
+ * SVM models produced by `kernlab` now use the formula method. This change was due to how `ksvm()` made indicator variables for factor predictors (with one-hot encodings). Since the ordinary formula method did not do this, the data are passed as-is to `ksvm()` so that the results are closer to what one would get if `ksmv()` were called directly. 
+ 
+ * MARS models produced by `earth` now use the formula method. 
+ 
+ * Under-the-hood changes were made so that non-standard data arguments in the modeling packages can be accomodated. (#315)
+ 
 ## New Features
 
  * A new main argument was added to `boost_tree()` called `stop_iter` for early stopping. The `xgb_train()` function gained arguments for early stopping and a percentage of data to leave out for a validation set. 

R/arguments.R

@@ -158,11 +158,11 @@ make_form_call <- function(object, env = NULL) {
 
   # add data arguments
   for (i in seq_along(data_args)) {
-    fit_args[[ names(data_args)[i] ]] <- sym(unname(data_args[i]))
+    fit_args[[ unname(data_args[i]) ]] <- sym(names(data_args)[i])
   }
 
   # sub in actual formula
-  fit_args[[ data_args["formula"] ]]  <- env$formula
+  fit_args[[ unname(data_args["formula"]) ]]  <- env$formula
 
   if (object$engine == "spark") {
     env$x <- env$data
@@ -186,8 +186,8 @@ make_xy_call <- function(object, target) {
     data_args <- object$method$fit$data
   }
 
-  object$method$fit$args[[ data_args["y"] ]] <- rlang::expr(y)
-  object$method$fit$args[[ data_args["x"] ]] <-
+  object$method$fit$args[[ unname(data_args["y"]) ]] <- rlang::expr(y)
+  object$method$fit$args[[ unname(data_args["x"]) ]] <-
     switch(
       target,
       none = rlang::expr(x),