const MAX_LEN=250, MIN_LEN=3;
fcn compress(text){ // !empty byte/text stream -->Data (byte stream)
   sink:=Data(); cnt:=Ref(0);
   write:='wrap(c,n){ // helper function
      while(n>MAX_LEN){
         sink.write(1); sink.write(MAX_LEN); sink.write(c);
	 n-=MAX_LEN;
      }
      if(n>MIN_LEN){ sink.write(1); sink.write(n); sink.write(c); }
      else { do(n) { sink.write(c); } }
   };
   text.reduce('wrap(a,b){
      if(a==b) cnt.inc();
      else{ write(a,cnt.value); cnt.set(1); }
      b
   },text[0]) : write(_,cnt.value);
   sink;
}