31.2 Top-Level Definitions, or Defuns
In Emacs, a major definition at the top level in the buffer,
something like a function, is called a defun. The name comes
from Lisp, but in Emacs we use it for all languages.
In many programming language modes, Emacs assumes that a defun is
any pair of parentheses (or braces, if the language uses braces this
way) that starts at the left margin. For example, in C, the body of a
function definition is a defun, usually recognized as an open-brace
that begins at the left margin1. A
variable's initializer can also count as a defun, if the open-brace
that begins the initializer is at the left margin.
However, some language modes provide their own code for recognizing
defuns in a way that suits the language syntax and conventions better.
