From eb9c70312bf38801a5a3e7a75c8038fd72a0f4d1 Mon Sep 17 00:00:00 2001
From: Randy Lai <randy.cs.lai@gmail.com>
Date: Sun, 11 Sep 2016 00:26:54 -0400
Subject: [PATCH] allow .Last.value for non-visible commands

---
 R/execution.r | 50 ++++++++++++++++++++++++++------------------------
 R/utils.r     |  2 +-
 2 files changed, 27 insertions(+), 25 deletions(-)

diff --git a/R/execution.r b/R/execution.r
index 42421612..87f7a23d 100644
--- a/R/execution.r
+++ b/R/execution.r
@@ -9,10 +9,10 @@ plot_builds_upon <- function(prev, current) {
     if (is.null(prev)) {
         return(TRUE)
     }
-    
+
     lprev <- length(prev[[1]])
     lcurrent <- length(current[[1]])
-    
+
     lcurrent >= lprev && identical(current[[1]][1:lprev], prev[[1]][1:lprev])
 }
 
@@ -30,29 +30,29 @@ ask <- function(prompt = '') {
 
 format_stack <- function(calls) {
     line_refs <- rep('', length(calls))
-    
+
     tb <- lapply(seq_along(calls), function(cl) {
         call <- calls[[cl]]
-        
+
         # first_line, first_byte, last_line, last_byte, first_column, last_column, first_parsed, last_parsed
         ref <- attr(call, 'srcref')
-        
+
         filename <- attr(ref, 'srcfile')$filename
-        
+
         if (!is.null(ref)) {
             f <- ref[[1]]
             l <- ref[[3]]
             lines <- if (f == l) f else paste0(f, '-', l)
             line_refs[[cl]] <<- paste0('   # at line ', lines, ' of file ', filename)
         }
-        
+
         white <- paste(rep(' ', nchar(format(cl))), collapse = '')
-        
+
         f.call <- format(call)
         line.prefix <- c(cl, rep(white, length(f.call) - 1))
         paste(paste0(line.prefix, '. ', f.call), collapse = '\n')
     })
-    
+
     paste0(tb, line_refs)
 }
 
@@ -91,7 +91,7 @@ display_data = function(data, metadata = NULL) {
         source = 'R display func',
         data = data,
         metadata = metadata))
-    
+
     invisible(TRUE)
 },
 
@@ -118,9 +118,9 @@ quit = function(save = 'default', status = 0, runLast = TRUE) {
 handle_error = function(e) tryCatch({
     log_debug('Error output: %s', toString(e))
     calls <- head(sys.calls()[-seq_len(nframe + 1L)], -3)
-    
+
     calls <- skip_repeated(calls)
-    
+
     msg <- paste0(toString(e), 'Traceback:\n')
     stack_info <- format_stack(calls)
 
@@ -160,16 +160,18 @@ handle_display_error = function(e) {
     send_error_msg(msg)
 },
 
-handle_value = function(obj) {
+handle_value = function(obj, visible) {
     log_debug('Value output...')
     mimebundle <- prepare_mimebundle_kernel(obj, .self$handle_display_error)
     if (length(intersect(class(obj), getOption('jupyter.pager_classes'))) > 0) {
         log_debug('Showing pager: %s', paste(capture.output(str(mimebundle$data)), collapse = '\n'))
         page(mimebundle)
     } else {
-        log_debug('Sending display_data: %s', paste(capture.output(str(mimebundle$data)), collapse = '\n'))
         set_last_value(obj)
-        send_response('display_data', current_request, 'iopub', mimebundle)
+        if (visible) {
+            log_debug('Sending display_data: %s', paste(capture.output(str(mimebundle$data)), collapse = '\n'))
+            send_response('display_data', current_request, 'iopub', mimebundle)
+        }
     }
 },
 
@@ -209,13 +211,13 @@ execute = function(request) {
     send_response('execute_input', request, 'iopub', list(
         code = request$content$code,
         execution_count = execution_count))
-        
+
     # Make the current request available to other functions
     current_request <<- request
     # reset ...
     payload <<- list()
     err <<- list()
-    
+
     # shade base::quit
     add_to_user_searchpath('quit', .self$quit)
     add_to_user_searchpath('q', .self$quit)
@@ -226,7 +228,7 @@ execute = function(request) {
         'stop()',
         stop_on_error = 1L,
         output_handler = new_output_handler(error = function(e) nframe <<- sys.nframe())))
-    
+
     oh <- if (is_silent()) {
         new_output_handler(
             text = identity,
@@ -244,13 +246,13 @@ execute = function(request) {
             error = .self$handle_error,
             value = .self$handle_value)
     }
-    
+
     interrupted <<- FALSE
     last_recorded_plot <<- NULL
     log_debug('Executing code: %s', request$content$code)
-    
+
     warn_unicode_on_windows(request$content$code, .self$send_error_msg)
-    
+
     tryCatch(
         evaluate(
             request$content$code,
@@ -259,11 +261,11 @@ execute = function(request) {
             stop_on_error = 1L),
         interrupt = function(cond) interrupted <<- TRUE,
         error = .self$handle_error) # evaluate does not catch errors in parsing
-    
+
     if (!is_silent() && !is.null(last_recorded_plot)) {
         send_plot(last_recorded_plot)
     }
-    
+
     if (interrupted) {
         reply_content <- list(
             status = 'abort')
@@ -278,7 +280,7 @@ execute = function(request) {
             payload = payload,
             user_expressions = namedlist())
     }
-    
+
     send_response('execute_reply', request, 'shell', reply_content)
 
     if (interrupted || !is.null(err$ename)) {
diff --git a/R/utils.r b/R/utils.r
index 305f7398..1bbd548c 100644
--- a/R/utils.r
+++ b/R/utils.r
@@ -4,7 +4,7 @@ ellip_h <- repr:::.char_fallback('\u22EF', '...')
 skip_repeated <- function(vec) {
     if (length(vec) == 0L)
         return(vec)
-    
+
     if (is.language(vec[[1]])) {  # rle does not work on language items
         ctb <- as.character(vec)
         enc <- rle(ctb)