Can the R prompt be a time?

Question

?option says this.

     ‘prompt’: a non-empty string to be used for R's prompt; should
          usually end in a blank (‘" "’).

Is it possible to make the prompt to include some dynamic stuffs, e.g., the current time?

Answer 1

You should take a look at the taskCallbackManager (https://developer.r-project.org/TaskHandlers.pdf). With prompt you can call the current time and save it. Example: options("prompt"=format(Sys.time(), "%H:%M:%S> ")). But this is fixed with the time it was set.

The doc for the function taskCallbackManager has the rest:

R> h <- taskCallbackManager()
R> h$add(function(expr, value, ok, visible) { 
+     options("prompt"=format(Sys.time(), "%H:%M:%S> ")); 
+             return(TRUE) }, 
+     name = "simpleHandler")
[1] "simpleHandler"
07:25:42> a <- 2
07:25:48>

This registers a callback that gets evaluated after each command completes.