scsh-ncurses/scheme/input-buffer.scm

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;;This is an application of the "scsh-ncurses" lib.
;;It consists of a buffer with input.
;;
;;At the beginning we only have an empty buffer for example.
;;You pass this buffer an char after char to the input-function,
;;which modifies the content of the buffer. In the standard-case
;;you get the characters from "wgetch".
;;
;;One brief example:
; ;
; ;
; ; (begin
; ; (define my-buffer (make-buffer-welcome 20 20 "test"))
; ; (init-screen)
; ; (define win (newwin 20 20 5 5))
; ; (box win (ascii->char 0) (ascii->char 0))
; ; (noecho)
; ; (keypad win #t)
; ; (set! my-buffer (print-command-buffer win my-buffer))
; ; (let loop ((ch (wgetch win)))
; ; (begin
; ; (wclear win)
; ; (box win (ascii->char 0) (ascii->char 0))
; ; (set! my-buffer (input my-buffer ch))
; ; (set! my-buffer (print-command-buffer win my-buffer))
; ; (if (= ch key-f1)
; ; (begin
; ; (echo)
; ; (endwin))
; ; (begin
; ; (set! my-buffer (cursor-right-pos win my-buffer))
; ; (loop (wgetch win)))))))
;;It is very esential, that you set keypad to true und call noecho!!!
;;record-type buffer
(define-record-type buffer buffer
(make-buffer text
pos-line
pos-col
pos-fin-ln
pos-y
pos-x
num-lines
num-cols
can-write
history-pos)
(text buffer-text set-buffer-text!)
(pos-line buffer-pos-line set-buffer-pos-line!)
(pos-col buffer-pos-col set-buffer-pos-col!)
(pos-fin-ln buffer-pos-fin-ln set-buffer-pos-fin-ln!)
(pos-y buffer-pos-y set-buffer-pos-y!)
(pos-x buffer-pos-x set-buffer-pos-x!)
(num-lines buffer-num-lines set-buffer-num-lines!)
(num-cols buffer-num-cols set-buffer-num-cols!)
(can-write buffer-can-write set-buffer-can-write!)
(history-pos buffer-history-pos set-buffer-history-pos!))
;;handle input
(define input
(lambda (buffer ch)
(let ((text (buffer-text buffer))
(pos-line (buffer-pos-line buffer))
(pos-col (buffer-pos-col buffer))
(pos-fin-ln (buffer-pos-fin-ln buffer))
(pos-y (buffer-pos-y buffer))
(pos-x (buffer-pos-x buffer))
(num-lines (buffer-num-lines buffer))
(num-cols (buffer-num-cols buffer))
(can-write (buffer-can-write buffer))
(history-pos (buffer-history-pos buffer)))
(begin
(cond
;;Enter
((= ch 10)
(begin
(set! text (append text (list "")))
(set! pos-line (+ pos-line 1))
(set! history-pos (- (length text) 1))
(set! pos-col 2)))
;;Backspace
((= ch key-backspace)
(if can-write
(if (< pos-col 3)
values
(begin
(set! text (remove-from-command-buffer text pos-col))
(set! pos-col (- pos-col 1))))
values))
;;Nav
((= ch key-up)
(if (< pos-fin-ln 2)
values
(let ((length-prev-line
(string-length
(list-ref text (- pos-line 2)))))
(begin
(set! can-write #f)
(set! pos-line (- pos-line 1))
(set! pos-col (+ length-prev-line 2))))))
((= ch key-down)
(let ((last-pos (length text)))
(if (>= pos-line last-pos)
values
(let ((length-next-line
(string-length
(list-ref text pos-line))))
(begin
(set! pos-col (+ length-next-line 2))
(set! pos-line (+ pos-line 1))
(if (= pos-line last-pos)
(set! can-write #t)))))))
((= ch key-left)
(if (<= pos-col 2)
values
(begin
(set! pos-col (- pos-col 1)))))
((= ch key-right)
(let ((line-length (string-length
(list-ref text
(- pos-line 1)))))
(if (>= pos-col (+ line-length 2))
values
(begin
(set! pos-col (+ pos-col 1))))))
;;Ctrl+a -> Pos 1
((= ch 1)
(begin
(set! pos-col 2)))
;;Ctrl-e -> End
((= ch 5)
(let ((line-length (string-length
(list-ref text (- pos-line 1)))))
(begin
(set! pos-col (+ line-length 2)))))
;;Ctrl+k -> Zeile l<>schen
((= ch 11)
(if can-write
(let ((text-front (sublist text 0 (- (length text) 1))))
(begin
(set! text (append text-front '("")))
(set! pos-col 2)))))
;;Ctrl+f -> History-forward
((= ch 6)
(if can-write
(begin
(if (< history-pos (- (length text) 1))
(set! history-pos (+ history-pos 1)))
(let ((rest (sublist text 0 (- (length text) 1)))
(hist (if (= history-pos (- (length text) 1))
""
(list-ref text history-pos))))
(set! text (append rest (list hist))))
(let ((line-length (string-length
(list-ref text (- (length text) 1)))))
(set! pos-col (+ line-length 2))))))
;;Ctrl+b -> History-back
((= ch 2)
(if can-write
(begin
(if (> history-pos 0)
(set! history-pos (- history-pos 1)))
(let ((rest (sublist text 0 (- (length text) 1)))
(hist (list-ref text history-pos)))
(set! text (append rest (list hist))))
(let ((line-length (string-length
(list-ref text (- (length text) 1)))))
(set! pos-col (+ line-length 2))))))
(else
(if (<= ch 255)
(if can-write
(begin
(begin
(set! text (add-to-command-buffer ch text pos-col))
(set! pos-col (+ pos-col 1)))
values))
values)))
(make-buffer text pos-line pos-col pos-fin-ln pos-y pos-x
num-lines num-cols can-write history-pos)))))
;;print content of the buffer into the specified window
(define print-command-buffer
(lambda (win buffer)
(let ((text (buffer-text buffer))
(pos-line (buffer-pos-line buffer))
(pos-col (buffer-pos-col buffer))
(pos-fin-ln (buffer-pos-fin-ln buffer))
(pos-y (buffer-pos-y buffer))
(pos-x (buffer-pos-x buffer))
(num-lines (buffer-num-lines buffer))
(num-cols (buffer-num-cols buffer))
(can-write (buffer-can-write buffer))
(history-pos (buffer-history-pos buffer)))
(let* ((l (get-right-command-lines text pos-fin-ln num-lines
pos-line num-cols))
(lines (car l)))
(begin
(set! pos-fin-ln (cdr l))
(let loop ((pos 1))
(if (> pos num-lines)
(make-buffer text pos-line pos-col pos-fin-ln pos-y
pos-x num-lines num-cols can-write history-pos)
(let ((line (list-ref lines (- pos 1))))
(begin
(mvwaddstr win pos 1 line)
(wrefresh win)
(loop (+ pos 1)))))))))))
;;compute the visible lines
(define get-right-command-lines
(lambda (text pos-fin-ln num-lines pos-line num-cols)
(let* ((res (all-commands-seperated text pos-line num-cols
pos-fin-ln ))
(all-lines-seperated (car res))
(num-all-lines (length all-lines-seperated)))
(begin
(set! pos-fin-ln (cdr res))
(if (>= pos-fin-ln num-lines)
;;aktive Zeile ist die unterste
(cons (sublist all-lines-seperated
(- pos-fin-ln num-lines)
num-lines)
pos-fin-ln)
(if (<= num-all-lines num-lines)
;;noch keine ganze Seite im Buffer
(cons (prepare-lines all-lines-seperated
num-lines (- pos-fin-ln 1))
pos-fin-ln)
;;scrollen auf der ersten Seite
(cons (sublist all-lines-seperated 0 num-lines)
pos-fin-ln)))))))
;;seperate all statements
(define all-commands-seperated
(lambda (commands pos-line num-cols pos-fin-ln)
(let loop ((act-pos 1)
(new '()))
(begin
(if (= act-pos pos-line)
(let* ((length-new (length new))
(first-el-old (list-ref commands (- act-pos 1)))
(seperated-act (seperate-line-com
first-el-old num-cols))
(length-act (length seperated-act)))
(set! pos-fin-ln (+ length-new length-act))))
(if (> act-pos (length commands))
(cons (reverse new) pos-fin-ln)
(let* ((first-el-old (list-ref commands (- act-pos 1)))
(seperated-fst-el-old
(seperate-line-com first-el-old num-cols)))
(loop (+ act-pos 1) (append seperated-fst-el-old new))))))))
;;seperate one statement
(define seperate-line-com
(lambda (line width)
(let loop ((new '())
(old line))
(if (> width (string-length old))
(if (= 0 (string-length old))
(if (equal? new '())
(add-prompts '(""))
(add-prompts new))
;new
(add-prompts (append (list old) new)))
;(append (list old) new))
(let ((next-line (substring old 0 width))
(rest-old (substring old width (string-length old))))
(loop (cons next-line new) rest-old))))))
;;add ">"
(define add-prompts
(lambda (l)
(let* ((lr (reverse l))
(old-first-el (list-ref lr 0))
(new-first-el (string-append ">" old-first-el))
(old-rest (list-tail lr 1)))
(let loop ((old old-rest)
(new (list new-first-el)))
(if (> (length old) 0)
(let* ((old-first-el (list-ref old 0))
(new-first-el (string-append " " old-first-el)))
(loop (list-tail old 1) (append new (list new-first-el))))
(reverse new))))))
;;Find the lines to print
(define prepare-lines
(lambda (l height pos)
(if (< (length l) height)
;; Liste zu kurz -> ""s hinzuf<75>gen
(let loop ((tmp-list l))
(if (= height (length tmp-list))
tmp-list
(loop (append tmp-list (list "")))))
;; Teilliste holen
(if (< pos height)
;;pos nicht ganz unten
(sublist l 0 height)
;;standard-Fall
(sublist l (- pos height) height)))))
;;Cursor
;;Put Cursor to the right position
(define cursor-right-pos
(lambda (win buffer)
(let ((text (buffer-text buffer))
(pos-line (buffer-pos-line buffer))
(pos-col (buffer-pos-col buffer))
(pos-fin-ln (buffer-pos-fin-ln buffer))
(pos-y (buffer-pos-y buffer))
(pos-x (buffer-pos-x buffer))
(num-lines (buffer-num-lines buffer))
(num-cols (buffer-num-cols buffer))
(can-write (buffer-can-write buffer))
(history-pos (buffer-history-pos buffer)))
(begin
;;zuerst mal y
(let* ((line (list-ref text (- pos-line 1)))
(offset (lines-from-fin-line num-cols pos-col line)))
(if (>= pos-fin-ln num-lines)
;;unterste Zeile
(set! pos-y (- num-lines offset))
;;sonst
(set! pos-y (- pos-fin-ln offset))))
(let ((posx (modulo pos-col num-cols)))
(if (<= posx 1)
(set! pos-x (+ num-cols posx))
(if (and (= posx 2)
(> pos-col num-cols))
(set! pos-x (+ num-cols 1))
(set! pos-x posx)))
(wmove win pos-y pos-x)
(wrefresh win)
(make-buffer text pos-line pos-col pos-fin-ln pos-y pos-x
num-lines num-cols can-write history-pos))))))
(define lines-from-fin-line
(lambda (num-cols pos-col line)
(let* ((lines (ceiling (/ (string-length line) num-cols)))
(end-pos (* lines num-cols)))
(if (= (string-length line) 0)
0
(let loop ((offset 0)
(end end-pos))
(if (<= (+ end 2) pos-col)
(- offset 1)
(loop (+ offset 1) (- end num-cols))))))))
;;Add one character to the buffer
(define add-to-command-buffer
(lambda (ch text pos-col)
(let* ((last-pos (- (length text) 1))
(old-last-el (list-ref text last-pos))
(old-rest (sublist text 0 last-pos))
(before-ch (substring old-last-el 0
(max 0 (- pos-col 2))))
(after-ch (substring old-last-el
(max 0 (- pos-col 2))
(string-length old-last-el)))
(new-last-el (string-append before-ch
(string (ascii->char ch))
after-ch)))
(append old-rest (list new-last-el)))))
;;Remove one character from the line (backspace)
(define remove-from-command-buffer
(lambda (text pos-col)
(let* ((last-pos (- (length text) 1))
(old-last-el (list-ref text last-pos))
(old-rest (sublist text 0 last-pos))
(before-ch (substring old-last-el 0
(max 0 (- pos-col 3))))
(after-ch (if (= pos-col
(+ (string-length old-last-el) 2))
""
(substring old-last-el
(max 0 (- pos-col 2))
(string-length old-last-el))))
(new-last-el (if (= pos-col
(+ (string-length old-last-el) 2))
before-ch
(string-append before-ch after-ch))))
(append old-rest (list new-last-el)))))
(define sublist
(lambda (l pos k)
(let ((tmp (list-tail l pos)))
(reverse (list-tail (reverse tmp)
(- (length tmp) k))))))
;;Create a fitting buffer for a window with box and a welcome-Message
;;If the message is "", the buffer starts in line one
(define make-buffer-welcome
(lambda (height width welcome-message)
(if (equal? "" welcome-message)
(make-buffer (list "") 1 2 1 1 2 (- height 2) (- width 3) #t 1)
(make-buffer (list welcome-message "") 2 2 2 2 2
(- height 2) (- width 3) #t 1) )))