       ctype ?-failindex var? class string
              ctype  determines  whether all characters in string
              are of the specified class.  It returns 1  if  they
              are  all of class, and 0 if they are not, or if the
              string  is  empty.   This  command  also   provides
              another  method  (besides  format and scan) of con-
              verting between an ASCII character and its  numeric
              value.  The following ctype commands are available:

            ctype ?-failindex var? alnum string
                   Tests that all characters  are  alphabetic  or
                   numeric characters as defined by the character
                   set.

            ctype ?-failindex var? alpha string
                   Tests that all characters are alphabetic char-
                   acters as defined by the character set.

            ctype ?-failindex var? ascii string
                   Tests that all characters are an ASCII charac-
                   ter (a non-negative number less than 0200).

            ctype char number
                   Converts the  numeric  value,  string,  to  an
                   ASCII  character.  Number must be in the range
                   0 through 255.

            ctype ?-failindex var? cntrl string
                   Tests that all characters are ``control  char-
                   acters'' as defined by the character set.

            ctype ?-failindex var? digit string
                   Tests  that  all  characters are valid decimal
                   digits, i.e. 0 through 9.

            ctype ?-failindex var? graph string
                   Tests that all characters within are any char-
                   acter  for  which  ctype print is true, except
                   for space characters.

            ctype ?-failindex var? lower string
                   Tests that all characters are  lowercase  let-
                   ters as defined by the character set.

            ctype ord character
                   Convert  a  character into its decimal numeric
                   value.  The first character of the  string  is
                   converted.

            ctype ?-failindex var? space string
                   Tests  that all characters are either a space,
                   horizontal-tab, carriage return, newline, ver-
                   tical-tab, or form-feed.
            ctype ?-failindex var? print string
                   Tests  that  all characters are a space or any
                   character for which ctype alnum or ctype punct
                   is  true  or  other  ``printing character'' as
                   defined by the character set.

            ctype ?-failindex var? punct string
                   Tests that all characters are made up  of  any
                   of  the  characters  other  than  the ones for
                   which alnum, cntrl, or space is true.

            ctype ?-failindex var? upper string
                   Tests that all characters are  uppercase  let-
                   ters as defined by the character set.

            ctype ?-failindex var? xdigit string
                   Tests  that all characters are valid hexadeci-
                   mal digits, that is 0 through 9, a  through  f
                   or A through F.

            If  -failindex  is  specified,  then  the  index into
            string of the first character that did not match  the
            class is returned in var.

       This command is provided by Extended Tcl.
