Literal examples

You can include literal examples that should not be subjected to markup. Such examples will be typeset in monospace, so this is well suited for source code and similar examples.

     #+BEGIN_EXAMPLE
     Some example from a text file.
     #+END_EXAMPLE

For simplicity when using small examples, you can also start the example lines with a colon:

     : Some example from a text file.

If the example is source code from a programming language, or any other text that can be marked up by font-lock in Emacs, you can ask for the example to look like the fontified Emacs buffer¹. This is done with the ‘src’ block, where you also need to specify the name of the major mode that should be used to fontify the example:

     #+BEGIN_SRC emacs-lisp
     (defun org-xor (a b)
        "Exclusive or."
        (if a (not b) b))
     #+END_SRC

Both in example and in src snippets, you can add a -n switch to the end of the BEGIN line, to get the lines of the example numbered. If you use a +n switch, the numbering from the previous numbered snippet will be continued in the current one. In literal examples, Org will interpret strings like ‘(ref:name)’ as labels, and use them as targets for special hyperlinks like [[(name)]] (i.e. the reference name enclosed in single parenthesis). In HTML, hoovering the mouse over such a link will remote-highlight the corresponding code line, which is kind of cool. If the example/src snippet is numbered, you can also add a -r switch. Then labels will be removed from the source code and the links will be replaced² with line numbers from the code listing. Here is an example:

     #+BEGIN_SRC emacs-lisp -n -r
     (save-excursion                  (ref:sc)
        (goto-char (point-min))       (ref:jump)
     #+END SRC
     In line [[(sc)]] we remember the current positon.  [[(jump)][Line (jump)]]
     jumps to point-min.

If the syntax for the label format conflicts with the language syntax, use a -l switch to change the format, for example ‘#+BEGIN_SRC pascal -n -r -l "((%s))"’. See also the variable org-coderef-label-format.

C-c '

Edit the source code example at point in its native mode. This works by switching to an indirect buffer, narrowing the buffer and switching to the other mode. You need to exit by pressing C-c ' again³. Fixed-width regions (where each line starts with a colon followed by a space) will be edited using artist-mode⁴ to allow creating ASCII drawings easily. Using this command in an empty line will create a new fixed-width region.

C-c l

Calling org-store-link while editing a source code example in a temporary buffer created with C-c ' will prompt for a label, make sure that it is unique in the current buffer, and insert it with the proper formatting like ‘(ref:label)’ at the end of the current line. Then the label is stored as a link ‘(label)’, for retrieval with C-c C-l.