$query =~ s/\s+/ /g ;      # that's the whitespace
  $query =~ s/\A\s// ;       # strip leading
  $query =~ s/\s\Z// ;       # strip trailing

  $query = lc($query) ;      # all lower case

  $query =~ s/(["'])((?:\\\1|\1\1|.)*?)\1/mash_s($1, $2)/eg ;
                             # Eliminate separators from quoted strings

  sub mash_s {
    my ($q, $s) = @_ ;
    $s =~ tr/0-9a-z/\\/c ;
    return $q.$s.$q ;
  } ;

##</code><code>##

  $query =~ s/([^ !#\$%()*,\/:;<=>?\@[\]^{|}~]+)/mash_l($1)/eg ;

  sub mash_l {
    my ($s) = @_ ;

    return $s if $s =~ /^(?:[a-z]+|\+|\-)$/ ;

    return 'N' if $s =~ /^[+-]?(?:
                                 (?:\d+(?:\.\d*)? | \.\d+) (?:e[+-]\d+)?
                                |(?:0(?:
                                        x[0-9a-f]+
                                       |b[01]+
                                      )
                                 )
                                |x'[0-9a-f]+'
                                |b'[01]+'
                               )$/x ;

    return 'S' if $s =~ /^(["']).*?\1$/ ;

    return $s ;
  } ;