USING: hashtables locals io assocs kernel io.encodings.utf8 io.files formatting ;
IN: count-letters

<PRIVATE

: count-from-stream ( -- counts )
  52 <hashtable>
  [ read1 dup ] [ over inc-at ] while
  drop ;

: print-counts ( counts -- )
  [ "%c: %d\n" printf ] assoc-each ;

PRIVATE>

: count-letters ( filename -- )
  utf8 [ count-from-stream ] with-file-reader
    print-counts ;