Editing Emacs Lisp (section)

===Byte code===
''Byte-compiling'' can make Emacs Lisp code execute faster. Emacs contains a [[compiler]] which can translate Emacs Lisp source files into a special representation termed [[bytecode]]. Emacs Lisp bytecode files have the [[filename suffix]] "<code>.elc</code>". Compared to source files, bytecode files load and run faster, occupy less disk space, and use less memory when loaded.

Bytecode still runs more slowly than primitives, but functions loaded as bytecode can be easily modified and re-loaded. In addition, bytecode files are platform-independent. The standard Emacs Lisp code distributed with Emacs is loaded as bytecode, although the matching source files are usually provided for the user's reference as well. User-supplied extensions are typically not byte-compiled, as they are neither as large nor as computationally intensive.