add Readme.md files to most examples

R/shinyui.R

@@ -161,7 +161,7 @@ writeShowcaseHead <- function(connection) {
      # Read lines from the Markdown file, join them to a single string separated
      # by literal \n (for JavaScript), escape quotes, and emit to a JavaScript
      # string literal. 
-     writeLines(paste('"', do.call(paste, as.list(c(gsub('"', '\"', readLines(mdfile)), sep = "\\n"))),
+     writeLines(paste('"', do.call(paste, as.list(c(gsub('"', '\\\\"', readLines(mdfile)), sep = "\\n"))),
                       '");', sep = ""), con = connection)
      writeLines('});', con = connection);
   }

inst/examples/02_text/Readme.md

@@ -0,0 +1 @@
+This example demonstrates output of raw text from R using the `renderPrint` function in `server.R` and the `verbatimTextOutput` function in `ui.R`. In this case, a textual summary of the data is shown using R's built-in `summary` function. 

inst/examples/03_reactivity/Readme.md

@@ -0,0 +1,5 @@
+This example demonstrates a core feature of Shiny: **reactivity**. In `server.R`, a reactive called `datasetInput` is declared. 
+
+Notice that the reactive expression depends on the input expression `input$dataset`, and that it's used by both the output expression `output$summary` and `output$view`. Try changing the dataset (using *Choose a dataset*) while looking at the reactive and then at the outputs; you will see first the reactive and then its dependencies flash. 
+
+Notice also that the reactive expression doesn't just update whenever anything changes--only the inputs it depends on will trigger an update. Change the "Caption" field and notice how only the `output$caption` expression is re-evaluated; the reactive and its dependents are left alone.

inst/examples/04_mpg/Readme.md

@@ -0,0 +1,4 @@
+This example demonstrates the following concepts:
+
+* **Global variables**: The `mpgData` variable is declared outside the `shinyServer` function. This makes it available anywhere inside `shinyServer`. The code in `server.R` outside `shinyServer` is only run once when the app starts up, so it can't contain user input.
+* **Reactive expressions**: `formulaText` is a reactive expression. Note how it re-evaluates when the Variable field is changed, but not when the Show Outliers box is ticked. 

inst/examples/05_sliders/Readme.md

@@ -0,0 +1,3 @@
+This example demonstrates Shiny's versatile `sliderInput` widget. 
+
+Slider inputs can be used to select single values, to select a continuous range of values, and even to animate over a range.

inst/examples/06_tabsets/Readme.md

@@ -0,0 +1,9 @@
+This example demonstrates the `tabsetPanel` and `tabPanel` widgets.
+
+Notice that outputs that are not visible are not re-evaluated until they become visible. Try this: 
+
+1. Scroll to the bottom of `server.R`
+2. Change the number of observations, and observe that only `output$plot` is evaluated.
+3. Click the Summary tab, and observe that `output$summary` is evaluated.
+4. Change the number of observations again, and observe that now only `output$summary` is evaluated.
+

inst/examples/07_widgets/Readme.md

@@ -0,0 +1,2 @@
+This example demonstrates some additional widgets included in Shiny, such as `helpText` and `submitButton`. The latter is used to delay rendering output until the user explicitly requests it.
+