From d16beaf59caf21af5ccfa4b723cd28b350a48576 Mon Sep 17 00:00:00 2001
From: Joe Cheng <joe@rstudio.org>
Date: Wed, 11 Apr 2012 11:23:14 -0700
Subject: [PATCH] Introduce chunk.end.is.terminator option

Also changes gfm mode to have ``` chunk.end instead of ````
---
 R/defaults.R |  3 ++-
 R/parser.R   | 20 ++++++++++++++++++++
 R/pattern.R  |  3 ++-
 3 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/R/defaults.R b/R/defaults.R
index f29d983581..b79484d22e 100644
--- a/R/defaults.R
+++ b/R/defaults.R
@@ -109,7 +109,8 @@ all_patterns =
                      ref.label = '^## @knitr (.*)$'),
 
        `md` = list(chunk.begin = '^``` \\{r(.*)\\}\\s*$',
-                   chunk.end = '^````\\s*$',
+                   chunk.end = '^```\\s*$',
+                   chunk.end.is.terminator = TRUE,
                    ref.chunk = '^\\s*<<(.*)>>\\s*$',
                    inline.code = '`r\\s+([^`]*)\\s*`',
                    global.options = '`ro\\s+([^`]*)\\s+or`',
diff --git a/R/parser.R b/R/parser.R
index 568eab01f4..227a40d5e7 100644
--- a/R/parser.R
+++ b/R/parser.R
@@ -16,6 +16,8 @@ split_file = function(path, lines = readLines(path, warn = FALSE), set.preamble
   
   blks = str_detect(lines, chunk.begin)
   txts = str_detect(lines, chunk.end)
+  if (isTRUE(as.logical(knit_patterns$get('chunk.end.is.terminator'))))
+    txts = filter_chunk_end(blks, txts)
   
   tmp = logical(n); tmp[blks | txts] = TRUE; lines[txts] = ''
   
@@ -271,3 +273,21 @@ parse_chunk = function(x) {
   }), use.names = FALSE)
   x
 }
+
+## filter chunk.end lines that don't actually end a chunk
+filter_chunk_end = function(chunk.begin, chunk.end) {
+  in.chunk = FALSE
+  fun = function(is.begin, is.end) {
+    if (in.chunk && is.end) {
+      in.chunk <<- FALSE
+      return(TRUE)
+    }
+    else if (!in.chunk && is.begin) {
+      in.chunk <<- TRUE
+      return(FALSE)
+    }
+    else
+      return(FALSE)
+  }
+  mapply(fun, chunk.begin, chunk.end)
+}
diff --git a/R/pattern.R b/R/pattern.R
index 6652df6ea8..56f491996f 100644
--- a/R/pattern.R
+++ b/R/pattern.R
@@ -1,5 +1,6 @@
 ## initial pattern list
-.pat.init = list(chunk.begin = NULL, chunk.end = NULL, chunk.code = NULL,
+.pat.init = list(chunk.begin = NULL, chunk.end = NULL, 
+                chunk.end.is.terminator = NULL, chunk.code = NULL,
                 inline.code = NULL, global.options = NULL, input.doc = NULL,
                 ref.chunk = NULL, header.begin = NULL, document.begin = NULL, 
                 ref.label = NULL)