add native support for Emacs Org-mode tables

DESCRIPTION

@@ -1,7 +1,7 @@
 Package: knitr
 Type: Package
 Title: A General-Purpose Package for Dynamic Report Generation in R
-Version: 1.43.14
+Version: 1.43.15
 Authors@R: c(
     person("Yihui", "Xie", role = c("aut", "cre"), email = "xie@yihui.name", comment = c(ORCID = "0000-0003-0645-5666")),
     person("Abhraneel", "Sarma", role = "ctb"),

NEWS.md

@@ -2,6 +2,8 @@
 
 ## NEW FEATURES
 
+- `kable()` can generate Emacs org-mode tables now via `kable(..., format = 'org')` (thanks, @xvrdm #1372, @maxecharel #2258).
+
 - Added support for the `qmd` (Quarto) output format to `spin()`, e.g., `spin('script.R', format = 'qmd') (thanks, @cderv, #2284).
 
 - `write_bib()` has a new argument `packageURL` to control whether to use a URL from the `DESCRIPTION` file or the one generated by `utils::citation()` (thanks, @dmurdoch, #2264).

R/table.R

@@ -17,11 +17,11 @@
 #'   returned value from \code{kable()}.
 #' @param format A character string. Possible values are \code{latex},
 #'   \code{html}, \code{pipe} (Pandoc's pipe tables), \code{simple} (Pandoc's
-#'   simple tables), \code{rst}, and \code{jira}. The value of this argument
-#'   will be automatically determined if the function is called within a
-#'   \pkg{knitr} document. The \code{format} value can also be set in the global
-#'   option \code{knitr.table.format}. If \code{format} is a function, it must
-#'   return a character string.
+#'   simple tables), \code{rst}, \code{jira}, and \code{org} (Emacs Org-mode).
+#'   The value of this argument will be automatically determined if the function
+#'   is called within a \pkg{knitr} document. The \code{format} value can also
+#'   be set in the global option \code{knitr.table.format}. If \code{format} is
+#'   a function, it must return a character string.
 #' @param digits Maximum number of digits for numeric columns, passed to
 #'   \code{round()}. This can also be a vector of length \code{ncol(x)}, to set
 #'   the number of digits for individual columns.
@@ -408,7 +408,7 @@ kable_mark = function(x, sep.row = c('=', '=', '='), sep.col = '  ', padding = 0
     ifelse(align == 'c', 2, 1)
   }
   l = pmax(l + padding, 3)  # at least of width 3 for Github Markdown
-  s = unlist(lapply(l, function(i) paste(rep(sep.row[2], i), collapse = '')))
+  s = strrep(sep.row[2], l)
   res = rbind(if (!is.na(sep.row[1])) s, cn, align.fun(s, align),
               x, if (!is.na(sep.row[3])) s)
   res = mat_pad(res, l, align)
@@ -431,7 +431,7 @@ kable_rst = function(x, rownames.name = '\\', ...) {
 }
 
 # Pandoc's pipe table
-kable_pipe = function(x, caption = NULL, padding = 1, ...) {
+kable_pipe = function(x, caption = NULL, padding = 1, caption.label = 'Table:', ...) {
   if (is.null(colnames(x))) colnames(x) = rep('', ncol(x))
   res = kable_mark(x, c(NA, '-', NA), '|', padding, align.fun = function(s, a) {
     if (is.null(a)) return(s)
@@ -442,7 +442,7 @@ kable_pipe = function(x, caption = NULL, padding = 1, ...) {
     s
   }, ...)
   res = sprintf('|%s|', res)
-  kable_pandoc_caption(res, caption)
+  kable_pandoc_caption(res, caption, caption.label)
 }
 
 # Pandoc's simple table
@@ -468,9 +468,20 @@ kable_jira = function(x, caption = NULL, padding = 1, ...) {
   kable_pandoc_caption(tab, caption)
 }
 
-kable_pandoc_caption = function(x, caption) {
+# Emacs Org-mode table
+kable_org = function(...) {
+  res = kable_pipe(..., caption.label = '#+CAPTION:')
+  i = grep('^[-:|]+$', res)  # find the line like |--:|---| under header
+  if (length(i)) {
+    i = i[1]
+    res[i] = gsub('(-|:)[|](-|:)', '\\1+\\2', res[i])  # use + as separator
+  }
+  res
+}
+
+kable_pandoc_caption = function(x, caption, label = 'Table:') {
   if (identical(caption, NA)) caption = NULL
-  if (length(caption)) c(paste('Table:', caption), "", x) else x
+  if (length(caption)) c(paste(label, caption), '', x) else x
 }
 
 # pad a matrix

tests/testit/test-table.R

@@ -39,6 +39,10 @@ assert('kable() works with the jira format', {
   (kable2(m, 'jira') %==% c('||   ||  x||  y||', '|a  |  1|  2|'))
 })
 
+assert('kable() works with the org format', {
+  (kable2(m, 'org') %==% c('|   |  x|  y|', '|:--+--:+--:|', '|a  |  1|  2|'))
+})
+
 assert('kable() does not add extra spaces to character columns', {
   (kable2(data.frame(x = c(1.2, 4.87), y = c('fooooo', 'bar')), 'latex') %==% '
 \\begin{tabular}{r|l}
@@ -136,7 +140,7 @@ assert('kable() works on matrices with NA colname', {
 x1 = matrix(NA, 0, 0)
 x2 = matrix(NA, 0, 1)
 x3 = matrix(NA, 1, 0)
-for (f in c('simple', 'html', 'latex', 'rst', 'jira')) {
+for (f in c('simple', 'html', 'latex', 'rst', 'jira', 'org')) {
   kable(x1, f)
   kable(x2, f)
   kable(x3, f)