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(texinfo)Functions Commands

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Functions and Similar Entities
------------------------------

  This section describes the commands for describing functions and
similar entities:

`@deffn CATEGORY NAME ARGUMENTS...'
     The `@deffn' command is the general definition command for
     functions, interactive commands, and similar entities that may take
     arguments.  You must choose a term to describe the category of
     entity being defined; for example, "Function" could be used if the
     entity is a function.  The `@deffn' command is written at the
     beginning of a line and is followed on the same line by the
     category of entity being described, the name of this particular
     entity, and its arguments, if any.  Terminate the definition with
     `@end deffn' on a line of its own.

     For example, here is a definition:

          @deffn Command forward-char nchars
          Move point forward @var{nchars} characters.
          @end deffn

     This shows a rather terse definition for a "command" named
     `forward-char' with one argument, NCHARS.

     `@deffn' prints argument names such as NCHARS in italics or upper
     case, as if `@var' had been used, because we think of these names
     as metasyntactic variables--they stand for the actual argument
     values.  Within the text of the description, write an argument name
     explicitly with `@var' to refer to the value of the argument.  In
     the example above, we used `@var{nchars}' in this way.

     The template for `@deffn' is:

          @deffn CATEGORY NAME ARGUMENTS...
          BODY-OF-DEFINITION
          @end deffn

`@defun NAME ARGUMENTS...'
     The `@defun' command is the definition command for functions.
     `@defun' is equivalent to `@deffn Function ...'.

     For example,

          @defun set symbol new-value
          Change the value of the symbol @var{symbol}
          to @var{new-value}.
          @end defun

     shows a rather terse definition for a function `set' whose
     arguments are SYMBOL and NEW-VALUE.  The argument names on the
     `@defun' line automatically appear in italics or upper case as if
     they were enclosed in `@var'.  Terminate the definition with `@end
     defun' on a line of its own.

     The template is:

          @defun FUNCTION-NAME ARGUMENTS...
          BODY-OF-DEFINITION
          @end defun

     `@defun' creates an entry in the index of functions.

`@defmac NAME ARGUMENTS...'
     The `@defmac' command is the definition command for macros.
     `@defmac' is equivalent to `@deffn Macro ...' and works like
     `@defun'.

`@defspec NAME ARGUMENTS...'
     The `@defspec' command is the definition command for special
     forms.  (In Lisp, a special form is an entity much like a function,
     Note: Special Forms..)  `@defspec' is
     equivalent to `@deffn {Special Form} ...' and works like `@defun'.