. file [ arg ... ]
       Read commands from file and execute them in  the  current  shell
       environment.

       If  file  does  not contain a slash, or if PATH_DIRS is set, the
       shell looks in the components of $path  to  find  the  directory
       containing  file.   Files  in the current directory are not read
       unless  `.'  appears  somewhere  in  $path.   If  a  file  named
       `file.zwc'  is  found,  is  newer than file, and is the compiled
       form (created with the zcompile builtin) of file, then  commands
       are read from that file instead of file.

       If  any  arguments  arg  are  given,  they become the positional
       parameters; the old positional parameters are restored when  the
       file is done executing.  However, if no arguments are given, the
       positional parameters remain those of the calling  context,  and
       no restoring is done.

       If  file  was  not  found  the return status is 127; if file was
       found but contained a syntax error the  return  status  is  126;
       else  the  return  status is the exit status of the last command
       executed.