(module text-ui mzscheme
  (require (lib "match.ss")
           (lib "pretty.ss")
           (lib "etc.ss")
           "front-end.ss")

  (define count
    (opt-lambda (s x [cutoff +inf.0])
      (match s
        [($ semantics language relation _ value?)
         (let loop ([n cutoff] [term (type-check s x)] [count 1])
           (if (or (zero? n) (value? term))
               count
               (loop (sub1 n) (next relation term) (add1 count))))])))

  (define trace
    (opt-lambda (s x [cutoff +inf.0])
      (match s
        [($ semantics language relation _ value?)
         (let ([term (type-check s x)])
           (let loop ([n cutoff] [term term] [trace (list term)])
             (if (or (zero? n) (value? term))
                 (reverse trace)
                 (let ([result (next relation term)])
                   (loop (sub1 n) result (cons result trace))))))])))

  (define pretty
    (opt-lambda (s x [cutoff +inf.0])
      (match s
        [($ semantics language relation _ value?)
         (parameterize ([pretty-print-columns 80])
           (let ([term (type-check s x)])
             (pretty-print term)
             (let loop ([n cutoff] [term term])
               (unless (or (zero? n) (value? term))
                 (let ([term (next relation term)])
                   (printf "---->\n")
                   (pretty-print term)
                   (loop (sub1 n) term))))))])))

  (provide count trace pretty))