[R] simplified the code; parameter style consistency

R-package/R/xgb.save.R

@@ -3,29 +3,25 @@
 #' Save xgboost model from xgboost or xgb.train
 #' 
 #' @param model the model object.
-#' @param fname the name of the binary file.
+#' @param fname the name of the file to write.
 #' 
 #' @examples
 #' data(agaricus.train, package='xgboost')
 #' data(agaricus.test, package='xgboost')
 #' train <- agaricus.train
 #' test <- agaricus.test
-#' bst <- xgboost(data = train$data, label = train$label, max.depth = 2, 
-#'                eta = 1, nthread = 2, nround = 2,objective = "binary:logistic")
+#' bst <- xgboost(data = train$data, label = train$label, max_depth = 2, 
+#'                eta = 1, nthread = 2, nrounds = 2,objective = "binary:logistic")
 #' xgb.save(bst, 'xgb.model')
 #' bst <- xgb.load('xgb.model')
 #' pred <- predict(bst, test$data)
 #' @export
 xgb.save <- function(model, fname) {
-  if (typeof(fname) != "character") {
-    stop("xgb.save: fname must be character")
-  }
-  if (class(model) == "xgb.Booster") {
-    model <- xgb.Booster.check(model)
-    .Call("XGBoosterSaveModel_R", model$handle, fname, PACKAGE = "xgboost")
-    return(TRUE)
-  }
-  stop("xgb.save: the input must be xgb.Booster. Use xgb.DMatrix.save to save
-       xgb.DMatrix object.")
-  return(FALSE)
+  if (typeof(fname) != "character")
+    stop("fname must be character")
+  if (class(model) != "xgb.Booster")
+    stop("the input must be xgb.Booster. Use xgb.DMatrix.save to save xgb.DMatrix object.")
+  
+  .Call("XGBoosterSaveModel_R", model$handle, fname, PACKAGE = "xgboost")
+  return(TRUE)
 }