(define-macro (LO var)
      (string->symbol
       (string-append (symbol->string var) "-" (symbol->string 'L))))

    (define-macro (HI var)
      (string->symbol
       (string-append (symbol->string var) "-" (symbol->string 'H))))

    (define-macro (wlet var lo hi body)
      `(let ((,(string->symbol
                (string-append (symbol->string var) "-" (symbol->string 'L)))
              ,lo)
             (,(string->symbol
                (string-append (symbol->string var) "-" (symbol->string 'H)))
              ,hi))
         ,body))