Document hl_lines feature for fenced_code and codehilite extensions.

1 files changed, 25 insertions, 0 deletions

diff --git a/docs/extensions/fenced_code_blocks.txt b/docs/extensions/fenced_code_blocks.txt
index c54c5bd..0148c80 100644
--- a/docs/extensions/fenced_code_blocks.txt
+++ b/docs/extensions/fenced_code_blocks.txt
@@ -35,6 +35,8 @@ Fenced code blocks can have a blank line as the first  and/or last line of a
 code block and they can also come immediately after a list item without becoming
 part of the list.
 
+### Language
+
 In addition to PHP Extra's syntax, you can define the language of the code 
 block for use by syntax highlighters etc. The language will be assigned as a 
 class attribute of the ``<code>`` element in the output. Therefore, you should 
@@ -66,6 +68,29 @@ The above will output:
 
 [Github]: http://github.github.com/github-flavored-markdown/
 
+### Emphasized Lines
+
+If [Pygments][] is installed, this extension can emphasize certain lines of
+code. By default, emphasized lines have a yellow background. This is useful to
+direct the reader's attention. The lines can be specified with PHP Extra's
+syntax:
+
+    ~~~~{.python hl_lines="1 3"}
+    # This line is emphasized
+    # This line isn't
+    # This line is emphasized
+
+... or with GitHub's:
+
+    ```python hl_lines="1 3"
+    # This line is emphasized
+    # This line isn't
+    # This line is emphasized
+
+(`hl_lines` is named for Pygments' "highlighted lines" option.)
+
+[Pygments]: http://pygments.org/
+
 Usage
 -----