functions [ {+|-}UXkmtuz ] [ name ... ]
functions -M mathfn [ min [ max [ shellfn ] ] ]
functions -M [ -m pattern ... ]
functions +M [ -m ] mathfn
       Equivalent  to  typeset -f, with the exception of the -M option.
       Use of the -M option may not be combined with any of the options
       handled by typeset -f.

       functions -M mathfn defines mathfn as the name of a mathematical
       function recognised in all forms  of  arithmetical  expressions;
       see  the  section  `Arithmetic  Evaluation'  in  zshmisc(1).  By
       default mathfn may take any number of comma-separated arguments.
       If  min  is given, it must have exactly min args; if min and max
       are both given, it must have at least min and at most max  args.
       max may be -1 to indicate that there is no upper limit.

       By  default  the  function is implemented by a shell function of
       the same name; if shellfn is specified it gives the name of  the
       corresponding  shell function while mathfn remains the name used
       in arithmetical expressions.  The name of the function in $0  is
       mathfn  (not shellfn as would usually be the case), provided the
       option FUNCTION ARGZERO is in effect.  The positional parameters
       in  the shell function correspond to the arguments of the mathe-
       matical function call.  The  result  of  the  last  arithmetical
       expression  evaluated inside the shell function (even if it is a
       form that normally only returns a status) gives  the  result  of
       the mathematical function.

       functions -M with no arguments lists all such user-defined func-
       tions in the same form as a  definition.   With  the  additional
       option  -m  and  a list of arguments, all functions whose mathfn
       matches one of the pattern arguments are listed.

       function +M removes the list of mathematical functions; with the
       additional  option  -m the arguments are treated as patterns and
       all functions whose mathfn  matches  the  pattern  are  removed.
       Note  that  the shell function implementing the behaviour is not
       removed (regardless of whether its name coincides with mathfn).

       For example, the following prints the cube of 3:

              zmath cube() { (( $1 * $1 * $1 )) }
              functions -M cube 1 1 zmath cube
              print $(( cube(3) ))

autoload [ {+|-}UXktz ] [ -w ] [ name ... ]
       Equivalent to functions -u, with the exception of -X/+X and -w.

       The  flag  -X  may be used only inside a shell function, and may
       not be followed by a name.  It causes the calling function to be
       marked for autoloading and then immediately loaded and executed,
       with the current array of positional  parameters  as  arguments.
       This  replaces  the  previous definition of the function.  If no
       function definition is found, an error is printed and the  func-
       tion remains undefined and marked for autoloading.

       The  flag  +X  attempts to load each name as an autoloaded func-
       tion, but does not execute it.  The exit status  is  zero  (suc-
       cess)  if  the function was not previously defined and a defini-
       tion for it was found.  This does not replace any existing defi-
       nition of the function.  The exit status is nonzero (failure) if
       the function was already  defined  or  when  no  definition  was
       found.   In  the  latter case the function remains undefined and
       marked for autoloading.  If ksh-style  autoloading  is  enabled,
       the  function created will contain the contents of the file plus
       a call to the function itself appended to it, thus giving normal
       ksh autoloading behaviour on the first call to the function.

       With the -w flag, the names are taken as names of files compiled
       with the zcompile builtin, and all functions defined in them are
       marked for autoloading.

       The flags -z and -k mark the function to be autoloaded in native
       or ksh emulation, as if the option KSH AUTOLOAD  were  unset  or
       were  set,  respectively.  The flags override the setting of the
       option at the time the function is loaded.
