EXAMPLES: Condition also on capabilities("tcltk")

Author: HenrikBengtsson

incl/tkprogressbar_handler.R

@@ -1,4 +1,4 @@
-if (requireNamespace("tcltk", quietly = TRUE)) {
+if (capabilities("tcltk") && requireNamespace("tcltk", quietly = TRUE)) {
   handlers("tkprogressbar")
   with_progress({ y <- slow_sum(1:10) })
   print(y)

incl/with_progress.R

@@ -15,7 +15,7 @@ with_progress({
 })
 
 ## Progress reported via tcltk::tkProgressBar
-if (requireNamespace("tcltk", quietly = TRUE)) {
+if (capabilities("tcltk") && requireNamespace("tcltk", quietly = TRUE)) {
   handlers("tkprogressbar")
   with_progress({
     y <- slow_sum(x)

man/tkprogressbar_handler.Rd

@@ -2,7 +2,7 @@ source("incl/start.R")
 
 options(progressr.clear = FALSE)
 
-if (requireNamespace("tcltk", quietly = TRUE)) {
+if (capabilities("tcltk") && requireNamespace("tcltk", quietly = TRUE)) {
   options(progressr.handlers = tkprogressbar_handler)
 }