Prompt user to install optional dependency

3 files changed, 16 insertions, 5 deletions

diff --git a/NAMESPACE b/NAMESPACE
index 92f1c4b..0508cde 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -10,5 +10,6 @@ importFrom(stats,pexp)
 importFrom(stats,pgamma)
 importFrom(stats,qexp)
 importFrom(stats,qgamma)
+importFrom(utils,install.packages)
 importFrom(utils,read.csv)
 importFrom(utils,write.csv)
diff --git a/R/app.R b/R/app.R
index feb052f..945f9e4 100644
--- a/R/app.R
+++ b/R/app.R
@@ -1,9 +1,19 @@
 #' Launch the Rnaught Web Application
 #'
+#' @importFrom utils install.packages
+#'
 #' @export
 app <- function() {
-  if (!requireNamespace("shiny", quietly = TRUE))
-    stop("The package 'shiny' must be installed to launch the Rnaught web application.")
+  if (!requireNamespace("shiny", quietly = TRUE)) {
+    answer <- readline(paste0("The package 'shiny' must be installed to ",
+      "launch the Rnaught web application.\nWould you like to install it? ",
+      "[Y/n] "))
+
+    if (answer == "Y" || answer == "y")
+      install.packages("shiny")
+    else
+      stop("Aborting.", call. = FALSE)
+  }
 
-  shiny::shinyApp(ui, server)
+  shiny::shinyApp(ui(), server)
 }
diff --git a/R/ui.R b/R/ui.R
index 4e4a500..5c6d420 100644
--- a/R/ui.R
+++ b/R/ui.R
@@ -1,4 +1,4 @@
-ui <- shiny::fluidPage(
+ui <- function() { shiny::fluidPage(
   # Title.
   shiny::titlePanel(shiny::HTML(
     paste0("Rnaught: An Estimation Suite for R", shiny::tags$sub("0")))),
@@ -194,4 +194,4 @@ ui <- shiny::fluidPage(
       )
     )
   )
-)
+)}