Fix examples with currentFib

_includes/tutorial/execution-scheduling.md

@@ -64,8 +64,8 @@ fib <- function(n) ifelse(n<3, 1, fib(n-1)+fib(n-2))
 shinyServer(function(input, output) {
   currentFib         <- reactive({ fib(as.numeric(input$n)) })
 
-  output$nthValue    <- renderText({ currentFib(as.numeric(input$n)) })
-  output$nthValueInv <- renderText({ 1 / currentFib(as.numeric(input$n)) })
+  output$nthValue    <- renderText({ currentFib() })
+  output$nthValueInv <- renderText({ 1 / currentFib() })
 })
 {% endhighlight %}
 

_includes/tutorial/reactivity-overview.md

@@ -92,8 +92,8 @@ fib <- function(n) ifelse(n<3, 1, fib(n-1)+fib(n-2))
 shinyServer(function(input, output) {
   currentFib         <- reactive({ fib(as.numeric(input$n)) })
 
-  output$nthValue    <- renderText({ currentFib(as.numeric(input$n)) })
-  output$nthValueInv <- renderText({ 1 / currentFib(as.numeric(input$n)) })
+  output$nthValue    <- renderText({ currentFib() })
+  output$nthValueInv <- renderText({ 1 / currentFib() })
 })
 {% endhighlight %}
 
@@ -103,15 +103,28 @@ Here is the new graph structure:
 ![Fibonacci app with conductor](reactivity_diagrams/conductor.png)
 
 
-Keep in mind that if your application tries to access reactive values or expressions from outside a reactive context &mdash; that is, outside of a reactive expression or observer &mdash; then it will result in an error. You can think of there being a reactive "world" which can see and change the non-reactive world, but the non-reactive world can't do the same to the reactive world. Code like this will not work, because the call to `fib()` is not in the reactive world, but it tries to access some that is, the reactive value `input$n`:
+Keep in mind that if your application tries to access reactive values or expressions from outside a reactive context &mdash; that is, outside of a reactive expression or observer &mdash; then it will result in an error. You can think of there being a reactive "world" which can see and change the non-reactive world, but the non-reactive world can't do the same to the reactive world. Code like this will not work, because the call to `fib()` is not in the reactive world (it's not in a `reactive()` or `renderXX()` call) but it tries to access something that is, the reactive value `input$n`:
 
 {% highlight r %}
 shinyServer(function(input, output) {
-  currentFib         <- fib(as.numeric(input$n))
-  output$nthValue    <- renderText({ currentFib })
+  # Will give error
+  currentFib      <- fib(as.numeric(input$n))
+  output$nthValue <- renderText({ currentFib })
 })
 {% endhighlight %}
 
+On the other hand, if `currentFib` is a function that accesses a reactive value, and that function is called within the reactive world, then it will work:
+
+{% highlight r %}
+shinyServer(function(input, output) {
+  # OK, as long as this is called from the reactive world:
+  currentFib <- function() {
+    fib(as.numeric(input$n))
+  }
+
+  output$nthValue <- renderText({ currentFib })
+})
+{% endhighlight %}
 
 ### Summary