Package requirements and loading, fix pkgdown site

NAMESPACE

@@ -53,6 +53,8 @@ S3method(print,rand_forest)
 S3method(print,surv_reg)
 S3method(print,svm_poly)
 S3method(print,svm_rbf)
+S3method(req_pkgs,model_fit)
+S3method(req_pkgs,model_spec)
 S3method(tidy,model_fit)
 S3method(tidy,nullmodel)
 S3method(translate,boost_tree)
@@ -144,6 +146,7 @@ export(predict_raw)
 export(predict_raw.model_fit)
 export(rand_forest)
 export(repair_call)
+export(req_pkgs)
 export(rpart_train)
 export(set_args)
 export(set_dependency)

NEWS.md

@@ -18,6 +18,10 @@
 
  * A function named `repair_call()` was added. This can help change the underlying models `call` object to better reflect what they would have obtained if the model function had been used directly (instead of via `parsnip`). This is only useful when the user chooses a formula interface and the model uses a formula interface. It will also be of limited use when a recipes is used to construct the feature set in `workflows` or `tune`. 
 
+ * The `predict()` function now checks to see if required modeling packages are installed. The packages are loaded (but not attached). (#249) (#308) (tidymodels/workflows#45)
+
+ * The function `req_pkgs()` is a user interface to determining the required packages.  (#308)
+
 # parsnip 0.1.1
 
 ## New Features

R/aaa.R

@@ -66,7 +66,7 @@ utils::globalVariables(
     'lab', 'original', 'predicted_label', 'prediction', 'value', 'type',
     "neighbors", ".submodels", "has_submodel", "max_neighbor", "max_penalty",
     "max_terms", "max_tree", "model", "name", "num_terms", "penalty", "trees",
-    "sub_neighbors", ".pred_class", "x", "y")
+    "sub_neighbors", ".pred_class", "x", "y", "predictor_indicators")
 )
 
 # nocov end

R/predict.R

@@ -117,6 +117,9 @@ predict.model_fit <- function(object, new_data, type = NULL, opts = list(), ...)
     return(NULL)
   }
 
+  check_installs(object$spec)
+  load_libs(object$spec, quiet = TRUE)
+
   other_args <- c("level", "std_error", "quantile") # "time" for survival probs later
   is_pred_arg <- names(the_dots) %in% other_args
   if (any(!is_pred_arg)) {

R/req_pkgs.R

@@ -0,0 +1,53 @@
+#' Determine required packages for a model
+#'
+#' @param x A model specification or fit.
+#' @param ... Not used.
+#' @return A character string of package names (if any).
+#' @details
+#' For a model specification, the engine must be set.
+#'
+#' The list does not include the `parsnip` package.
+#' @examples
+#' should_fail <- try(req_pkgs(linear_reg()), silent = TRUE)
+#' should_fail
+#'
+#' linear_reg() %>%
+#'   set_engine("glmnet") %>%
+#'   req_pkgs()
+#'
+#' linear_reg() %>%
+#'   set_engine("lm") %>%
+#'   fit(mpg ~ ., data = mtcars) %>%
+#'   req_pkgs()
+#' @export
+req_pkgs <- function(x, ...) {
+  UseMethod("req_pkgs")
+}
+
+#' @export
+#' @rdname req_pkgs
+req_pkgs.model_spec <- function(x, ...) {
+  if (is.null(x$engine)) {
+    rlang::abort("Please set an engine.")
+  }
+  get_pkgs(x)
+}
+
+#' @export
+#' @rdname req_pkgs
+req_pkgs.model_fit <- function(x, ...) {
+  get_pkgs(x$spec)
+}
+
+get_pkgs <- function(x) {
+  cls <- class(x)[1]
+  pkgs <-
+    get_from_env(paste0(cls, "_pkgs")) %>%
+    dplyr::filter(engine == x$engine)
+  res <- pkgs$pkg[[1]]
+  if (length(res) == 0) {
+    res <- character(0)
+  }
+  res
+}
+

docs/dev/pkgdown.css

@@ -244,14 +244,14 @@ nav[data-toggle='toc'] .nav .nav > .active:focus > a {
 
 .ref-index th {font-weight: normal;}
 
-.ref-index td {vertical-align: top; min-width: 100px}
+.ref-index td {vertical-align: top;}
 .ref-index .icon {width: 40px;}
 .ref-index .alias {width: 40%;}
 .ref-index-icons .alias {width: calc(40% - 40px);}
 .ref-index .title {width: 60%;}
 
 .ref-arguments th {text-align: right; padding-right: 10px;}
-.ref-arguments th, .ref-arguments td {vertical-align: top; min-width: 100px}
+.ref-arguments th, .ref-arguments td {vertical-align: top;}
 .ref-arguments .name {width: 20%;}
 .ref-arguments .desc {width: 80%;}
 

docs/dev/pkgdown.yml

@@ -1,14 +1,14 @@
 pandoc: 2.9.2.1
-pkgdown: 1.5.1.9000
-pkgdown_sha: ac78596154e403df5f4e683f2185d88225a0fea6
+pkgdown: 1.5.1
+pkgdown_sha: ~
 articles:
   Classification: articles/Classification.html
   Models: articles/Models.html
   Regression: articles/Regression.html
   Scratch: articles/Scratch.html
   Submodels: articles/Submodels.html
   parsnip_Intro: parsnip_Intro.html
-last_built: 2020-05-27T00:06Z
+last_built: 2020-05-30T23:54Z
 urls:
   reference: https://parsnip.tidymodels.org/reference
   article: https://parsnip.tidymodels.org/articles