15 Working with Source Code

Source code here refers to any plain text collection of computer instructions, possibly with comments, written using a human-readable programming language. Org can manage source code in an Org document when the source code is identified with begin and end markers. Working with source code begins with identifying source code blocks. A source code block can be placed almost anywhere in an Org document; it is not restricted to the preamble or the end of the document. However, Org cannot manage a source code block if it is placed inside an Org comment or within a fixed width section.

Here is an example source code block in the Emacs Lisp language:

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

Source code blocks are one of many Org block types, which also include “center", “comment", “dynamic", “example", “export", “quote", “special", and “verse". This section pertains to blocks between ‘#+BEGIN_SRC’ and ‘#+END_SRC’.

Details of Org’s facilities for working with source code are described in the following sections.

• Features Overview		Enjoy the versatility of source blocks.
• Structure of Code Blocks		Code block syntax described.
• Using Header Arguments		Different ways to set header arguments.
• Environment of a Code Block		Arguments, sessions, working directory...
• Evaluating Code Blocks		Place results of evaluation in the Org buffer.
• Results of Evaluation		Choosing a results type, post-processing...
• Exporting Code Blocks		Export contents and/or results.
• Extracting Source Code		Create pure source code files.
• Languages		List of supported code block languages.
• Editing Source Code		Language major-mode editing.
• Noweb Reference Syntax		Literate programming in Org mode.
• Library of Babel		Use and contribute to a library of useful code blocks.
• Key bindings and Useful Functions		Work quickly with code blocks.
• Batch Execution		Call functions from the command line.