$ include "seed7_05.s7i";
  include "chartype.s7i";

const func char: doChar (in boolean: doReverse) is func
  result
    var char: delimiter is ' ';
  local
    var char: ch is ' ';
  begin
    ch := getc(IN);
    if ch in letter_char then
      if doReverse then
        delimiter := doChar(doReverse);
        write(ch);
      else
        write(ch);
        delimiter := doChar(doReverse);
      end if;
    else
      delimiter := ch;
    end if;
  end func;

const proc: main is func
  local
    var char: delimiter is ' ';
    var boolean: doReverse is FALSE;
  begin
    repeat
      delimiter := doChar(doReverse);
      write(delimiter);
      doReverse := not doReverse;
    until delimiter = '.';
    writeln;
  end func;