Fix displaying

IRkernel · Mar 29, 2016 · a0d8a85 · a0d8a85
1 parent d3c3407
commit a0d8a85
Showing 1 changed file with 34 additions and 27 deletions.
diff --git a/R/execution.r b/R/execution.r
@@ -203,41 +203,48 @@ execute = function(request) {
             # to convert itself to something else (and don't output anything to the console) and the
             # returned obj is then printed again.
             print_return <<- list(visible=TRUE, value=obj)
-            send_even_if_no_print <- FALSE
             while(print_return$visible) {
                 data[['text/plain']] <- paste(capture.output(print_return <<- withVisible(print(print_return$value))), collapse = '\n')
-                if (print_return$visible) repr_even_if_no_print <- TRUE
+                if (print_return$visible){
+                    log_debug("Found visible return from print (cls: %s)", paste(class(obj), collapse=", "))
+                    obj <- print_return$value
+                }
+            }
+
+            # Sometimes, print(obj) does not print anything and we try to mimic that by not
+            # displaying anything in that case, even if our own repr_xxx functions would show
+            # something for the object.
+            if (nchar(data[['text/plain']]) > 0){
+                log_debug("Nothing printed for value")
+                return()
             }
-            obj <- print_return$value
 
-            if (send_even_if_no_print || nchar(data[['text/plain']]) > 0) {
-                if (getOption('jupyter.rich_display')) {
-                    for (mime in getOption('jupyter.display_mimetypes')) {
-                        # Use withCallingHandlers as that shows the inner stacktrace:
-                        # https://stackoverflow.com/questions/15282471/get-stack-trace-on-trycatched-error-in-r
-                        # the tryCatch is  still needed to prevent the error from showing
-                        # up outside further up the stack :-/
-                        tryCatch(withCallingHandlers({
-                                r <- mime2repr[[mime]](obj)
-                                if (!is.null(r)) {
-                                    data[[mime]] <- r
-                                    # Isolating full html pages (putting them in an iframe)
-                                    if (identical(mime, 'text/html')) {
-                                        if (grepl("<html.*>", r, ignore.case = TRUE)){
-                                            log_debug("Found full html page: %s", strtrim(r, 100))
-                                            metadata[[mime]] <- list(isolated = TRUE)
-                                        }
+            if (getOption('jupyter.rich_display')) {
+                for (mime in getOption('jupyter.display_mimetypes')) {
+                    # Use withCallingHandlers as that shows the inner stacktrace:
+                    # https://stackoverflow.com/questions/15282471/get-stack-trace-on-trycatched-error-in-r
+                    # the tryCatch is  still needed to prevent the error from showing
+                    # up outside further up the stack :-/
+                    tryCatch(withCallingHandlers({
+                            r <- mime2repr[[mime]](obj)
+                            if (!is.null(r)) {
+                                data[[mime]] <- r
+                                # Isolating full html pages (putting them in an iframe)
+                                if (identical(mime, 'text/html')) {
+                                    if (grepl("<html.*>", r, ignore.case = TRUE)){
+                                        log_debug("Found full html page: %s", strtrim(r, 100))
+                                        metadata[[mime]] <- list(isolated = TRUE)
                                     }
                                 }
-                            }, error = handle_display_error),
-                            error=function(x){})
-                    }
+                            }
+                        }, error = handle_display_error),
+                        error=function(x){})
                 }
-                log_debug("Sending display_data: %s", paste(capture.output(str(data)), collapse = "\n"))
-                send_response('display_data', request, 'iopub', list(
-                    data = data,
-                    metadata = metadata))
             }
+            log_debug("Sending display_data: %s", paste(capture.output(str(data)), collapse = "\n"))
+            send_response('display_data', request, 'iopub', list(
+                data = data,
+                metadata = metadata))
         }
 
         stream <- function(output, streamname) {