!PAMSET: set user selection of GROUPSEP and KEYFLAG
%include "inc:util.imp"
%begin
%integer i,j,k
%integer char1,char2,sym
%predicate ok(%integer char)
  %false %if char < ' '
  %false %if 'a' <= char!32 <= 'z'
  %false %if '0' <= char <= '9'
  %false %if char = '!' %or char = ','
  %true
%end
  prompt("GroupSeparator then Keyflag:")
  %cycle
    %cycle
      readsymbol(sym);  char1 = sym
      %if char1 >= ' ' %start
        readsymbol(sym);  char2 = sym
        %if char2 >= ' ' %start
          readsymbol(sym)
          %exit %if sym = nl
        %finish
      %finish
      printstring(" Definition must be precisely two symbols then RETURN")
      newline
    %repeat
    %if ok(char1) %start
      %if ok(char2) %start
        %if char2 # ' ' %start
          %exit %if char2 # char1
          printstring(" Choices must be different")
        %else
          printstring(" Keyword flag cannot be space")
        %finish
      %else
        printstring(" ".tostring(char2)." is not a valid choice")
      %finish
    %else
      printstring(" ".tostring(char1)." is not a valid choice")
    %finish
    newline
    readsymbol(sym) %while sym # nl
  %repeat
  pam_groupsep = char1
  pam_keyflag = char2
%endofprogram