add figure captioning support for shiny.tag/shiny.tag.list objects

Author: cpsievert

R/output.R

@@ -465,7 +465,7 @@ wrap.knit_asis = function(x, options, inline = FALSE) {
     # store metadata in an object named of the form .hash_meta when cache=TRUE
     if (length(m) && options$cache == 3)
       assign(cache_meta_name(options$hash), m, envir = knit_global())
-    if (inherits(x, 'knit_asis_htmlwidget')) {
+    if (inherits(x, c('knit_asis_htmlwidget', 'knit_asis_shiny_tag'))) {
       options$fig.cur = plot_counter()
       options = reduce_plot_opts(options)
       return(add_html_caption(options, x))

R/utils.R

@@ -752,6 +752,8 @@ knit_handlers = function(fun, options) {
     # the figure caption to it later in wrap.knit_asis
     if (inherits(x, 'htmlwidget'))
       class(res$value) = c(class(res$value), 'knit_asis_htmlwidget')
+    if (inherits(x, c('shiny.tag', 'shiny.tag.list')))
+      class(res$value) = c(class(res$value), 'knit_asis_shiny_tag')
     if (res$visible) res$value else invisible(res$value)
   }
   if (length(formals(fun)) < 2)