From ec0909c09131931346c9f0a3346f94f4aab83706 Mon Sep 17 00:00:00 2001
From: Jan Schulz <jasc@gmx.net>
Date: Tue, 10 May 2016 13:37:08 +0200
Subject: [PATCH 1/2] Add better way to extend base_display

The current way overwrites the function in IRkernel, but R CMD check complains about this. So add a way to use the options system to overwrite the function.
---
 R/display.R | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/R/display.R b/R/display.R
index d8e42e2..6c52e52 100644
--- a/R/display.R
+++ b/R/display.R
@@ -2,8 +2,12 @@
 #' @importFrom stats setNames
 namedlist <- function() setNames(list(), character(0))
 
-base_display <- function(data, metadata) {
-    warning("IR_display can only be used from the IPython R kernel and R magic.")
+base_display <- function(data, metadata = NULL) {
+    if (is.function(getOption('jupyter.base_display_func'))) {
+        getOption('jupyter.base_display_func')(data, metadata)
+    } else {
+        warning('IR_display can only be used from the IPython R kernel and R magic.')
+    }
 }
 
 #' Display data by mimetype, with optional alternative representations.

From 02c00666fed9f25e35f9ad84edaa6a4c8aa5dc2b Mon Sep 17 00:00:00 2001
From: Jan Schulz <jasc@gmx.net>
Date: Tue, 10 May 2016 13:41:01 +0200
Subject: [PATCH 2/2] Make base_diplay depend on a set function in options

Should be a bit faster but fails more horrible if a user submits a wrong functions there...
---
 R/display.R | 6 +-----
 R/options.r | 6 +++++-
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/R/display.R b/R/display.R
index 6c52e52..9cf2571 100644
--- a/R/display.R
+++ b/R/display.R
@@ -3,11 +3,7 @@
 namedlist <- function() setNames(list(), character(0))
 
 base_display <- function(data, metadata = NULL) {
-    if (is.function(getOption('jupyter.base_display_func'))) {
-        getOption('jupyter.base_display_func')(data, metadata)
-    } else {
-        warning('IR_display can only be used from the IPython R kernel and R magic.')
-    }
+    getOption('jupyter.base_display_func')(data, metadata)
 }
 
 #' Display data by mimetype, with optional alternative representations.
diff --git a/R/options.r b/R/options.r
index f1c89d9..e50c142 100644
--- a/R/options.r
+++ b/R/options.r
@@ -12,7 +12,11 @@ opt.defaults <- list(
         'application/pdf',
         'image/png',
         'image/jpeg',
-        'image/svg+xml')
+        'image/svg+xml'),
+    jupyter.base_display_func = function(data,  metadata = NULL){
+        warning('IRdisplay can only be used from the IPython R kernel and R magic.')
+    }
+    
 )
 
 .onLoad <- function(libname = NULL, pkgname = NULL) {