root/lang/zu/interpreter/scheme/trunk/lib/nt/textgraph.scm

;;;
;;; TextGraph - ported from yhara's Ruby implementation, by naoya_t
;;;
(define-module nt.textgraph
  (export
;   make-cell
;   cell=?
;   make-charmap
;   make-parser
   parse-textgraph
   ))

(select-module nt.textgraph)

(define undef-object (if #f #f))

(use srfi-1) ; drop-right
(use srfi-13) ; string-trim
(use gauche.sequence) ; ref

;;
;; Cell
;;
(define (make-cell x y w h raw-content)
  (cond ((or (< x 0) (< y 0)) (error "x or y value too small"))
                ((or (< w 2) (< h 2)) (error "w or h value too small"))
                (else (lambda (m)
                                (case m
                                  ((x) x)
                                  ((y) y)
                                  ((w) w)
                                  ((h) h)
                                  ((includes?) (lambda (tx ty) (and (<= x tx (+ x w -1))
                                                                                                        (<= y ty (+ y h -1)))))
                                  ((raw-content) raw-content)
                                  ((content) (string-trim-both raw-content))
                                  ((to-str) (format "[~d ~d ~d ~d \"~a\"]" x y w h (string-trim-both raw-content)))
                                  (else undef-object) ))
                          )))

(define (cell=? c1 c2)
  (and (= [c1'x] [c2'x])
           (= [c1'y] [c2'y])
           (= [c1'w] [c2'w])
           (= [c1'h] [c2'h])
           (string=? [c1'raw-content] [c2'raw-content])))

;;
;; CharMap
;;
(define (string->lines str)
  (drop-right (string-split str #[\r\n])
                          1))

(define (make-charmap str)
  (define (partition str)
        (map string->list
                 (string->lines str)))

  (let* ([data (partition str)]
                 [width (apply max (map length data))]
                 [height (length data)]
                 )

        (define (x-in-range? x)
          (and (<= 0 x) (< x width)))
        (define (y-in-range? y)
          (and (<= 0 y) (< y height)))

        (define (char-at x y) ; [](x,y)
;         (if (and (x-in-range? x) (y-in-range? y))
;                 (ref (ref data y) x)
;                 undef-object))
          (if (y-in-range? y)
                  (let1 line (ref data y)
                        (if (and (<= 0 x) (< x (length line)))
                                (ref line x)
                                undef-object))
                  undef-object))

        (define (map-char proc) ; takes (lambda (x y char) ...)
          (map-with-index (lambda (y line)
                                                (map-with-index (lambda (x char)
                                                                                  (apply proc (list x y char))
                                                                                  )
                                                                                line)
                                                )
                                          data))

        (define (each-char proc) ; takes (lambda (x y char) ...)
          (for-each-with-index (lambda (y line)
                                                         (for-each-with-index (lambda (x char)
                                                                                                        (apply proc (list x y char))
                                                                                                        )
                                                                                                  line)
                                                         )
                                                   data))

        (lambda (m)
          (case m
                ((raw-data) data)
                ((width) width)
                ((height) height)
                ((x-in-range?) x-in-range?)
                ((y-in-range?) y-in-range?)
                ((char-at) char-at)
                ((map-char) map-char)
                ((each-char) each-char)
                (else undef-object)))
        ))

;;
;; Graph
;;
(define (make-graph cells links)
;  (format #t "(make-graph ~a ~a)\n" cells links)
  (define (dump)
        (for-each-with-index
         (lambda (i cell) (format #t "~d) ~a\n" i [cell'to-str]))
         cells)
        (for-each
         (lambda (link) (format #t "~d --> ~d\n" (car link) (cdr link)))
         links))

  (lambda (m)
        (case m
          ((cells) cells)
          ((links) links)
          ((dump) (dump))
          (else undef-object))))

(define (make-coord x y)
  (lambda (m)
        (case m
          ((x) x)
          ((y) y)
          ((to-str) (format "(~d,~d)" x y))
          (else undef-object))))

(define (coord=? co1 co2)
  (and (= [co1'x] [co2'x])
           (= [co1'y] [co2'y])))

;;
;; Parser
;;
(define (make-parser str)
  (let1 charmap (make-charmap str)
        
        (define (collect-chars char)
          (remove! null?
                           (apply append!
                                          ([charmap'map-char] (lambda (x y c)
                                                                                        (if (eq? c char) (make-coord x y) '())
                                                                                        )
                                           ))))

        (define (find-horizontal-end x y dir goal-ch)
          (let1 dx (if dir 1 -1)
                (let loop ([tx (+ x dx)] [ty y])
                  (cond ((not ([charmap'x-in-range?] tx)) #f)
                                ((eq? goal-ch ([charmap'char-at] tx ty)) (make-coord tx ty))
                                (else (loop (+ tx dx) ty))))
                ))
        (define (find-vertical-end x y dir goal-ch)
          (let1 dy (if dir 1 -1)
                (let loop ([tx x] [ty (+ y dy)])
                  (cond ((not ([charmap'y-in-range?] ty)) #f)
                                ((eq? goal-ch ([charmap'char-at] tx ty)) (make-coord tx ty))
                                (else (loop tx (+ ty dy)))))
                ))

        (define (cell? x y)
          (if (and (memq ([charmap'char-at] (+ x 1) y) '(#\- #\v #\+))
                           (memq ([charmap'char-at] x (+ y 1)) '(#\| #\> #\+)))
                  (let* ([rt (find-horizontal-end x y #t #\*)]
                                 [lb (find-vertical-end x y #t #\*)]
                                 [lb-r (find-horizontal-end x [lb'y] #t #\*)]
                                 [rt-b (find-vertical-end [rt'x] y #t #\*)])
                        (if (and rt lb lb-r rt-b)
                                (if (coord=? lb-r rt-b)
                                        (make-coord (+ (- [rt'x] x) 1) (+ (- [lb'y] y) 1))
                                        #f)
                                #f) )
                  #f))

        (define (get-str x y w h)
          (string-join (map (lambda (ty)
                                                  (list->string (map (lambda (tx)
                                                                                           ([charmap'char-at] tx ty))
                                                                                         (iota (- w 2) (+ x 1)) )))
                                                (iota (- h 2) (+ y 1)) )))

        (define (collect-cells)
          (remove! null?
                           (map (lambda (coord)
                                          (let ([x (coord'x)]
                                                        [y (coord'y)])
                                                (let1 wh (cell? x y)
                                                  (if wh
                                                          (let ([w (wh'x)]
                                                                        [h (wh'y)])
                                                                (make-cell x y w h (get-str x y w h)))
                                                          '())
                                                  )))
                                        (collect-chars #\*)
                                        )))

        (define (find-links cells)
          (map (lambda (coord)
                         (let ([x (coord'x)]
                                   [y (coord'y)])
                           (let1 p (or (find-horizontal-end x y #t #\>)
                                                   (find-horizontal-end x y #f #\<)
                                                   (find-vertical-end x y #t #\v)
                                                   (find-vertical-end x y #f #\^))
                                 (cons (cell-at cells x y)
                                           (cell-at cells [p'x] [p'y]))
                                 )))
                   (collect-chars #\+)))

        (define (cell-at cells x y)
          (find-index
           (lambda (cell) ([cell'includes?] x y))
           cells))

        (define (get-direction x y)
          (cond ((memq ([charmap'char-at] (+ x 1) y) '(#\- #\>)) (list 1 0 #\>))
                        ((memq ([charmap'char-at] x (+ y 1)) '(#\| #\v)) (list 0 1 #\v))
                        ((memq ([charmap'char-at] (- x 1) y) '(#\- #\<)) (list -1 0 #\<))
                        ((memq ([charmap'char-at] x (- y 1)) '(#\| #\^)) (list 0 -1 #\^))
                        (else (error "can't decide direction"))))

        (define (parse)
          (let* ([cells (collect-cells)]
                         [links (find-links cells)])
                (make-graph cells links)))

        (lambda (m)
          (case m
                ((collect-chars) collect-chars)
                ((collect-cells) (collect-cells))
                ((parse) (parse))
;               ((dump) (dump))
                (else undef-object)))
        ))

(define (parse-textgraph str)
  [(make-parser str)'parse])

(provide "nt/textgraph")
;;EOF