
(module eval racket/base
  (require "manual.ss"
           "struct.ss"
           "scheme.ss"
           "decode.ss"
           racket/file
           racket/sandbox
           racket/promise
           racket/string
           (for-syntax racket/base))

  (provide interaction
           interaction-eval
           interaction-eval-show
           racketblock+eval (rename-out [racketblock+eval schemeblock+eval])
           racketmod+eval (rename-out [racketmod+eval schememod+eval])
           def+int
           defs+int
           examples
           examples*
           defexamples
           defexamples*
           as-examples
           
           make-base-eval
           make-base-eval-factory
           make-eval-factory
           close-eval

           scribble-eval-handler)

  (define scribble-eval-handler (make-parameter 
                                 (lambda (ev c? x)
                                   (ev x))))

  (define image-counter 0)

  (define maxlen 60)

  (namespace-require 'racket/base)
  (namespace-require '(for-syntax racket/base))

  (define (literal-string style s)
    (let ([m (regexp-match #rx"^(.*)(  +)(.*)$" s)])
      (if m
          (make-element #f
                        (list (literal-string style (cadr m))
                              (hspace (string-length (caddr m)))
                              (literal-string style (cadddr m))))
          (make-element style (list s)))))

  (define (format-output str style)
    (if (string=? "" str)
        null
        (list
         (list
          (make-flow 
           (list
            (let ([s (regexp-split #rx"\n"
                                   (regexp-replace #rx"\n$"
                                                   str
                                                   ""))])
              (if (= 1 (length s))
                  (make-paragraph
                   (list
                    (hspace 2)
                    (literal-string style (car s))))
                  (make-table
                   #f
                   (map (lambda (s)
                          (list (make-flow (list (make-paragraph
                                                  (list
                                                   (hspace 2)
                                                   (literal-string style s)))))))
                        s))))))))))

  (define (interleave title expr-paras val-list+outputs)
    (make-table
     #f
     (append
      (if title (list (list (make-flow (list title)))) null)
      (let loop ([expr-paras expr-paras]
                 [val-list+outputs val-list+outputs]
                 [first? #t])
        (if (null? expr-paras)
            null
            (append
             (list (list (let ([p (car expr-paras)])
                           (if (flow? p)
                               p
                               (make-flow (list p))))))
             (format-output (cadar val-list+outputs) output-color)
             (format-output (caddar val-list+outputs) error-color)
             (if (string? (caar val-list+outputs))
                 ;; Error result case:
                 (map
                  (lambda (s)
                    (car (format-output s error-color)))
                  (filter
                   (lambda (s) (not (equal? s "")))
                   (let sloop ([s (caar val-list+outputs)])
                     (apply
                      append
                      (map (lambda (s)
                             (if ((string-length s) . > . maxlen)
                                 ;; break the error message into multiple lines:
                                 (let loop ([pos (sub1 maxlen)])
                                   (cond
                                    [(zero? pos) (cons (substring s 0 maxlen)
                                                       (sloop (substring s maxlen)))]
                                    [(char-whitespace? (string-ref s pos))
                                     (cons (substring s 0 pos)
                                           (sloop (substring s (add1 pos))))]
                                    [else (loop (sub1 pos))]))
                                 (list s)))
                           (regexp-split #rx"\n" s))))))
                 ;; Normal result case:
                 (let ([val-list (caar val-list+outputs)])
                   (if (equal? val-list (list (void)))
                       null
                       (map (lambda (v)
                              (list (make-flow (list (make-paragraph 
                                                      (list
                                                       (hspace 2)
                                                       (elem #:style result-color
                                                             (to-element/no-color v #:expr? (print-as-expression)))))))))
                            val-list))))
             (loop (cdr expr-paras)
                   (cdr val-list+outputs)
                    #f)))))))

  (define (extract s . ops)
    (let loop ([s s][ops ops])
      (cond
       [(null? ops) s]
       [(syntax? s) (loop (syntax-e s) ops)]
       [else (loop ((car ops) s) (cdr ops))])))

  (define ((do-eval ev) s)
    (let loop ([s s][expect #f])
      (syntax-case s (code:comment eval:alts eval:check)
        [(code:line v (code:comment . rest))
         (loop (extract s cdr car) expect)]
        [(code:comment . rest)
         (list (list (void)) "" "")]
        [(eval:alts p e)
         (loop (extract s cdr cdr car) expect)]
        [(eval:check e expect)
         (loop (extract s cdr car)
               (list (syntax->datum (datum->syntax #f (extract s cdr cdr car)))))]
        [else
         (let ([r (with-handlers ([(lambda (x)
                                     (not (exn:break? x)))
                                   (lambda (e)
                                     (list (if (exn? e)
                                               (exn-message e)
                                               (format "uncaught exception: ~s" e))
                                           (get-output ev)
                                           (get-error-output ev)))])
                    (list (let ([v (do-plain-eval ev s #t)])
                            (make-reader-graph (copy-value v (make-hasheq))))
                          (get-output ev)
                          (get-error-output ev)))])
           (when expect
             (let ([expect (do-plain-eval ev (car expect) #t)])
               (unless (equal? (car r) expect)
                 (raise-syntax-error 'eval "example result check failed" s))))
           r)])))
                   

  (define (install ht v v2)
    (hash-set! ht v v2)
    v2)

  ;; Since we evaluate everything in an interaction before we typeset,
  ;;  copy each value to avoid side-effects.
  (define (copy-value v ht)
    (cond
     [(and v (hash-ref ht v #f))
      => (lambda (v) v)]
     [(syntax? v) (make-literal-syntax v)]
     [(string? v) (install ht v (string-copy v))]
     [(bytes? v) (install ht v (bytes-copy v))]
     [(pair? v) 
      (let ([ph (make-placeholder #f)])
        (hash-set! ht v ph)
        (placeholder-set! ph
                          (cons (copy-value (car v) ht)
                                (copy-value (cdr v) ht)))
        ph)]
     [(mpair? v) (let ([p (mcons #f #f)])
                   (hash-set! ht v p)
                   (set-mcar! p (copy-value (mcar v) ht))
                   (set-mcdr! p (copy-value (mcdr v) ht))
                   p)]
     [(vector? v) (let ([v2 (make-vector (vector-length v))])
                    (hash-set! ht v v2)
                    (let loop ([i (vector-length v2)])
                      (unless (zero? i)
                        (let ([i (sub1 i)])
                          (vector-set! v2 i (copy-value (vector-ref v i) ht))
                          (loop i))))
                    v2)]
     [(box? v) (let ([v2 (box #f)])
                 (hash-set! ht v v2)
                 (set-box! v2 (copy-value (unbox v) ht))
                 v2)]
     [(hash? v) (let ([ph (make-placeholder #f)])
                  (hash-set! ht v ph)
                  (let ([a (hash-map v (lambda (k v)
                                         (cons (copy-value k ht)
                                               (copy-value v ht))))])
                    (placeholder-set!
                     ph
                     ((if (hash-eq? v)
                          make-hasheq-placeholder
                          (if (hash-eqv? v)
                              make-hasheqv-placeholder
                              make-hash-placeholder))
                      a)))
                  ph)]
     [else v]))
            
  (define (strip-comments stx)
    (cond
     [(syntax? stx)
      (datum->syntax stx
                     (strip-comments (syntax-e stx))
                     stx
                     stx
                     stx)]
      [(pair? stx)
       (let ([a (car stx)]
             [comment? (lambda (a)
                         (and (pair? a)
                              (or (eq? (car a) 'code:comment)
                                  (and (identifier? (car a))
                                       (eq? (syntax-e (car a)) 'code:comment)))))])
         (if (or (comment? a)
                 (and (syntax? a) (comment? (syntax-e a))))
             (strip-comments (cdr stx))
             (cons (strip-comments a)
                   (strip-comments (cdr stx)))))]
      [(eq? stx 'code:blank) (void)]
      [else stx]))

  (define (make-base-eval)
    (call-with-trusted-sandbox-configuration
     (lambda ()
       (parameterize ([sandbox-output 'string]
                      [sandbox-error-output 'string]
                      [sandbox-propagate-breaks #f])
         (make-evaluator '(begin))))))

  (define (make-base-eval-factory mod-paths)
    (let ([ns (delay (let ([ns (make-base-empty-namespace)])
                       (parameterize ([current-namespace ns])
                         (for-each
                          (lambda (mod-path)
                            (dynamic-require mod-path #f))
                          mod-paths))
                       ns))])
      (lambda ()
        (let ([ev (make-base-eval)]
              [ns (force ns)])
          ((scribble-eval-handler) 
           ev #f
           `(,(lambda ()
                (for-each (lambda (mod-path) 
                            (namespace-attach-module ns mod-path))
                          mod-paths))))
          ev))))

  (define (make-eval-factory mod-paths)
    (let ([base-factory (make-base-eval-factory mod-paths)])
      (lambda ()
        (let ([ev (base-factory)])
          ((scribble-eval-handler) 
           ev #f
           `(,(lambda ()
                (for-each (lambda (mod-path) (namespace-require mod-path))
                          mod-paths))))
          ev))))

  (define (close-eval e)
    (kill-evaluator e)
    "")

  (define (do-plain-eval ev s catching-exns?)
    (parameterize ([sandbox-propagate-breaks #f])
      (call-with-values (lambda () 
                          ((scribble-eval-handler) 
                           ev
                           catching-exns? 
                           (let ([s (strip-comments s)])
                             (cond
                              [(syntax? s)
                               (syntax-case s (module)
                                 [(module . _rest)
                                  (syntax->datum s)]
                                 [_else s])]
                              [(bytes? s)
                               `(begin ,s)]
                              [(string? s)
                               `(begin ,s)]
                              [else s]))))
        list)))

  (define-syntax-rule (quote-expr e) 'e)

  (define (do-interaction-eval ev e)
    (parameterize ([current-command-line-arguments #()])
      (do-plain-eval (or ev (make-base-eval)) e #f))
    "")

  (define-syntax interaction-eval
    (syntax-rules ()
      [(_ #:eval ev e) (do-interaction-eval ev (quote-expr e))]
      [(_ e) (do-interaction-eval #f (quote-expr e))]))


  (define (show-val v)
    (elem #:style result-color
          (to-element/no-color v #:expr? (print-as-expression))))

  (define (do-interaction-eval-show ev e)
    (parameterize ([current-command-line-arguments #()])
      (show-val (car (do-plain-eval (or ev (make-base-eval)) e #f)))))

  (define-syntax interaction-eval-show
    (syntax-rules ()
      [(_ #:eval ev e) (do-interaction-eval-show ev (quote-expr e))]
      [(_ e) (do-interaction-eval-show #f (quote-expr e))]))

  (define-syntax racketinput*
    (syntax-rules (eval:alts code:comment)
      [(_ (code:comment . rest)) (racketblock (code:comment . rest))]
      [(_ (eval:alts a b)) (racketinput* a)]
      [(_ e) (racketinput e)]))

  (define-code racketblock+line (to-paragraph/prefix (hspace 2) 
                                                     (hspace 2)
                                                     (list " ")))

  (define-syntax (racketdefinput* stx)
    (syntax-case stx (define define-values define-struct)
      [(_ (define . rest))
       (syntax-case stx ()
         [(_ e) #'(racketblock+line e)])]
      [(_ (define-values . rest))
       (syntax-case stx ()
         [(_ e) #'(racketblock+line e)])]
      [(_ (define-struct . rest))
       (syntax-case stx ()
         [(_ e) #'(racketblock+line e)])]
      [(_ (code:line (define . rest) . rest2))
       (syntax-case stx ()
         [(_ e) #'(racketblock+line e)])]
      [(_ e) #'(racketinput* e)]))

  (define (do-titled-interaction ev t shows evals)
    (interleave t
                shows
                (map (do-eval ev) evals)))

  (define-syntax titled-interaction
    (syntax-rules ()
      [(_ #:eval ev t racketinput* e ...)
       (do-titled-interaction ev t (list (racketinput* e) ...) (list (quote-expr e) ...))]
      [(_ t racketinput* e ...)
       (titled-interaction #:eval (make-base-eval) t racketinput* e ...)]))

  (define-syntax interaction
    (syntax-rules ()
      [(_ #:eval ev e ...) (titled-interaction #:eval ev #f racketinput* e ...)]
      [(_ e ...) (titled-interaction #f racketinput* e ...)]))

  (define-syntax racketblock+eval
    (syntax-rules ()
      [(_ #:eval ev e ...)
       (let ([eva ev])
         (#%expression
          (begin (interaction-eval #:eval eva e) ...
                 (racketblock e ...))))]
      [(_ e ...)
       (racketblock+eval #:eval (make-base-eval) e ...)]))

  (define-syntax racketmod+eval
    (syntax-rules ()
      [(_ #:eval ev name e ...)
       (let ([eva ev])
         (#%expression
          (begin (interaction-eval #:eval eva e) ...
                 (racketmod name e ...))))]
      [(_ name e ...)
       (racketmod+eval #:eval (make-base-eval) name e ...)]))

  (define-syntax def+int
    (syntax-rules ()
      [(_ #:eval ev def e ...)
       (let ([eva ev])
         (column (list (racketblock+eval #:eval eva def)
                       blank-line
                       (interaction #:eval eva e ...))))]
      [(_ def e ...) 
       (def+int #:eval (make-base-eval) def e ...)]))

  (define-syntax defs+int
    (syntax-rules ()
      [(_ #:eval ev [def ...] e ...)
       (let ([eva ev])
         (column (list (racketblock+eval #:eval eva def ...)
                       blank-line
                       (interaction #:eval eva e ...))))]
      [(_ [def ...] e ...)
       (defs+int #:eval (make-base-eval) [def ...] e ...)]))

  (define example-title
    (make-paragraph (list "Example:")))
  (define examples-title
    (make-paragraph (list "Examples:")))

  (define-syntax pick-example-title
    (syntax-rules ()
      [(_ e) example-title]
      [(_ . _) examples-title]))

  (define-syntax examples
    (syntax-rules ()
      [(_ #:eval ev e ...)
       (titled-interaction #:eval ev (pick-example-title e ...) racketinput* e ...)]
      [(_ e ...)
       (titled-interaction (pick-example-title e ...)  racketinput* e ...)]))
  (define-syntax examples*
    (syntax-rules ()
      [(_ #:eval ev example-title e ...)
       (titled-interaction #:eval ev example-title racketinput* e ...)]
      [(_ example-title e ...)
       (titled-interaction example-title racketinput* e ...)]))
  (define-syntax defexamples
    (syntax-rules ()
      [(_ #:eval ev e ...)
       (titled-interaction #:eval ev (pick-example-title e ...)  racketdefinput* e ...)]
      [(_ e ...)
       (titled-interaction (pick-example-title e ...)  racketdefinput* e ...)]))
  (define-syntax defexamples*
    (syntax-rules ()
      [(_ #:eval ev example-title e ...)
       (titled-interaction #:eval ev example-title racketdefinput* e ...)]
      [(_ example-title e ...)
       (titled-interaction example-title racketdefinput* e ...)]))

  (define blank-line (make-paragraph (list 'nbsp)))

  (define (column l)
    (make-table #f (map
                    (lambda (t)
                      (list (make-flow (list t))))
                    l)))

  (define (do-splice l)
    (cond
     [(null? l) null]
     [(splice? (car l)) (append (splice-run (car l))
                                (do-splice (cdr l)))]
     [else (cons (car l) (do-splice (cdr l)))]))

  (define as-examples
    (case-lambda
     [(t) (as-examples examples-title t)]
     [(example-title t)
      (make-table #f
                  (list
                   (list (make-flow (list example-title)))
                   (list (make-flow (do-splice (list t))))))])))
