From a415aed7e6f7d970648caeaf9f8745baf0f63d53 Mon Sep 17 00:00:00 2001
From: Hadley Wickham <h.wickham@gmail.com>
Date: Tue, 3 Sep 2019 09:13:43 -0500
Subject: [PATCH 1/2] Implement print.reactivevalues

---
 NAMESPACE                               | 1 +
 R/reactives.R                           | 8 ++++++++
 R/utils.R                               | 4 ++++
 tests/testthat/print-reactiveValues.txt | 6 ++++++
 tests/testthat/test-reactivity.r        | 6 ++++++
 5 files changed, 25 insertions(+)
 create mode 100644 tests/testthat/print-reactiveValues.txt

diff --git a/NAMESPACE b/NAMESPACE
index 086c3aca8..d7cc9866a 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -26,6 +26,7 @@ S3method(format,reactiveExpr)
 S3method(format,reactiveVal)
 S3method(names,reactivevalues)
 S3method(print,reactive)
+S3method(print,reactivevalues)
 S3method(print,shiny.appobj)
 S3method(str,reactivevalues)
 export("conditionStackTrace<-")
diff --git a/R/reactives.R b/R/reactives.R
index 162769359..736b086d4 100644
--- a/R/reactives.R
+++ b/R/reactives.R
@@ -590,6 +590,14 @@ checkName <- function(x) {
   )
 }
 
+#' @export
+print.reactivevalues <- function(x, ...) {
+  impl <- .subset2(x, "impl")
+  cat_line("<ReactiveValues>")
+  cat_line("  Values:   ", paste0(impl$.values$keys(sort = TRUE), collapse = ", "))
+  cat_line("  Readonly: ", .subset2(x, "readonly"))
+}
+
 #' Checks whether an object is a reactivevalues object
 #'
 #' Checks whether its argument is a reactivevalues object.
diff --git a/R/utils.R b/R/utils.R
index 67690eb8b..a6874b85b 100644
--- a/R/utils.R
+++ b/R/utils.R
@@ -1800,3 +1800,7 @@ constantTimeEquals <- function(raw1, raw2) {
 
   sum(as.integer(xor(raw1, raw2))) == 0
 }
+
+cat_line <- function(...) {
+  cat(paste(..., "\n", collapse = ""))
+}
diff --git a/tests/testthat/print-reactiveValues.txt b/tests/testthat/print-reactiveValues.txt
new file mode 100644
index 000000000..c5c4c4dfd
--- /dev/null
+++ b/tests/testthat/print-reactiveValues.txt
@@ -0,0 +1,6 @@
+> x <- reactiveValues(x = 1, y = 2, z = 3)
+> x
+<ReactiveValues> 
+  Values:    x, y, z 
+  Readonly:  FALSE 
+
diff --git a/tests/testthat/test-reactivity.r b/tests/testthat/test-reactivity.r
index 55a34e91a..a1fe47f6f 100644
--- a/tests/testthat/test-reactivity.r
+++ b/tests/testthat/test-reactivity.r
@@ -122,6 +122,12 @@ test_that("ReactiveValues", {
   expect_error(values$a <- 1)
 })
 
+test_that("reactiveValues() has useful print method", {
+  verify_output(test_path("print-reactiveValues.txt"), {
+    x <- reactiveValues(x = 1, y = 2, z = 3)
+    x
+  })
+})
 
 # Test for overreactivity. funcB has an indirect dependency on valueA (via
 # funcA) and also a direct dependency on valueA. When valueA changes, funcB

From eb0162dccf19e2df1e718e7a9329b800afcfeef6 Mon Sep 17 00:00:00 2001
From: Hadley Wickham <h.wickham@gmail.com>
Date: Tue, 3 Sep 2019 09:17:02 -0500
Subject: [PATCH 2/2] Add basic print method for shiny.render.function

So at least the user isn't exposed to a bunch on internals
---
 NAMESPACE         | 1 +
 R/shinywrappers.R | 5 +++++
 2 files changed, 6 insertions(+)

diff --git a/NAMESPACE b/NAMESPACE
index d7cc9866a..dd5a4caea 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -28,6 +28,7 @@ S3method(names,reactivevalues)
 S3method(print,reactive)
 S3method(print,reactivevalues)
 S3method(print,shiny.appobj)
+S3method(print,shiny.render.function)
 S3method(str,reactivevalues)
 export("conditionStackTrace<-")
 export(..stacktraceoff..)
diff --git a/R/shinywrappers.R b/R/shinywrappers.R
index e7b2ba3bd..27c11bfd7 100644
--- a/R/shinywrappers.R
+++ b/R/shinywrappers.R
@@ -52,6 +52,11 @@ markRenderFunction <- function(uiFunc, renderFunc, outputArgs = list()) {
             hasExecuted = hasExecuted)
 }
 
+#' @export
+print.shiny.render.function <- function(x, ...) {
+  cat_line("<shiny.render.function>")
+}
+
 #' Implement render functions
 #'
 #' @param func A function without parameters, that returns user data. If the