! A simple program that generates Excel spreadsheet column id corresponding to given column number.
! For example:
!   14 - N
!   26 - Z
!   27 - AA
!   29 - AC
: alphabet    (   -- seq  ) CHAR: A CHAR: Z [a,b] ;
: nth-char    ( n -- char ) 1 - alphabet nth 1string ;
: column-id   ( i -- str  ) dup 26 <= [ nth-char ] [ (column-id) ] if ;
: (column-id) ( i -- str  ) 26 [ /i column-id ] [ mod nth-char ] 2bi append ;