(define (has-ssyntax-char? string i)
    (and (>= i 0)
         (or (let ((c (string-ref string i)))
               (or (eqv? c #\:) (eqv? c #\~) 
                   (eqv? c #\&)                
                   (eqv? c #\%)                
                   ;(eqv? c #\_) 
                   (eqv? c #\.)(eqv? c #\!)))
             (has-ssyntax-char? string (- i 1)))))

  (define (expand-ssyntax sym)
    ((cond ((or (insym? #\: sym) (insym? #\~ sym)) expand-compose)
           ((or (insym? #\. sym) (insym? #\! sym)(insym? #\% sym)) expand-sexpr)
           ((insym? #\& sym) expand-and)
       ;   ((insym? #\_ sym) expand-curry)
           (#t (error "Unknown ssyntax" sym)))
   sym))

  (define (build-sexpr toks orig)
    (cond ((null? toks)
           'get)	    
          ((null? (cdr toks))
           (chars->value (car toks)))
          (#t
           (list (build-sexpr (cddr toks) orig)
                 (cond ((eqv? (cadr toks) #\!)
                        (list 'quote (chars->value (car toks))))
                       ((eqv? (cadr toks) #\%)
                         (list 'string (list 'quote (chars->value (car toks)))))
                       ((or (eqv? (car toks) #\.)(eqv? (car toks) #\!)(eqv? (car toks) #\$)(eqv? (car toks) #\%))
                         (err "Bad ssyntax" orig))
                       (#t 
                       (chars->value (car toks))))))))

  arc> (= test (obj "a" "my a val" "b" "my b val"))
  #hash(("a" . "my a val") ("b" . "my b val"))

  arc> test%a
  "my a val"