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beautiful-racket/beautiful-racket-lib/br/indent.rkt

129 lines
3.7 KiB
Racket

#lang racket/base
(require racket/class)
(provide (all-defined-out))
(module+ test
(require racket/gui/base rackunit)
(define t (new text%))
(define result (send t insert-port (open-input-string "foo\n ar\n m"))))
(define indent-width 2)
(define (char text pos)
(send text get-character pos))
(module+ test
(check-equal? (char t 0) #\f)
(check-equal? (char t 2) #\o)
(check-equal? (char t 3) #\newline)
(check-equal? (char t 10) #\m)
(check-equal? (char t 11) #\nul))
(define (line text pos)
(send text position-line pos))
(module+ test
(check-equal? (line t 0) 0)
(check-equal? (line t 2) 0)
(check-equal? (line t 5) 1)
(check-equal? (line t 10) 2)
(check-equal? (line t 11) 2))
(define (previous-line text pos)
(define this-line (line text pos))
(and (this-line . > . 0) (sub1 this-line)))
(module+ test
(check-equal? (previous-line t 0) #f)
(check-equal? (previous-line t 2) #f)
(check-equal? (previous-line t 5) 0)
(check-equal? (previous-line t 10) 1)
(check-equal? (previous-line t 11) 1))
(define (next-line text pos)
(define last (send text last-line))
(define this-line (line text pos))
(and (this-line . < . last) (add1 this-line)))
(module+ test
(check-equal? (next-line t 0) 1)
(check-equal? (next-line t 2) 1)
(check-equal? (next-line t 5) 2)
(check-equal? (next-line t 10) #f)
(check-equal? (next-line t 11) #f))
(define (valid-line? text line)
(<= 0 line (send text last-line)))
(define (line-start text line)
(and (valid-line? text line)
(send text line-start-position line)))
(module+ test
(check-equal? (line-start t 0) 0)
(check-equal? (line-start t 1) 4)
(check-equal? (line-start t 2) 8)
(check-equal? (line-start t 3) #f))
(define (line-end text line)
(and (valid-line? text line)
(send text line-end-position line)))
(module+ test
(check-equal? (line-end t 0) 3)
(check-equal? (line-end t 1) 7)
(check-equal? (line-end t 2) 11)
(check-equal? (line-end t 3) #f))
(define (first-visible-char-pos text start end)
;; private
(for*/first ([pos (in-range start end (if (start . > . end) -1 1))]
[c (in-value (char text pos))]
#:when (not (char-blank? c)))
pos))
(define (line-start-visible text line)
(define start (line-start text line))
(define end (line-end text line))
(and start end (first-visible-char-pos text start end)))
(module+ test
(check-equal? (line-start-visible t 0) 0)
(check-equal? (line-start-visible t 1) 5)
(check-equal? (line-start-visible t 2) 10)
(check-equal? (line-start-visible t 3) #f))
(define (line-end-visible text line)
(define start+1 (line-end text line)) ; start before newline
(define end+1 (line-start text line))
(and start+1 end+1 (first-visible-char-pos text (sub1 start+1) (sub1 end+1))))
(module+ test
(check-equal? (line-end-visible t 0) 2)
(check-equal? (line-end-visible t 1) 6)
(check-equal? (line-end-visible t 2) 10)
(check-equal? (line-end-visible t 3) #f))
(define (line-indent text line)
(and (valid-line? text line)
(let ([lsv (line-start-visible text line)])
(and lsv ; could be #f
(- (line-start-visible text line) (line-start text line))))))
(module+ test
(check-equal? (line-indent t 0) 0)
(check-equal? (line-indent t 1) 1)
(check-equal? (line-indent t 2) 2)
(check-equal? (line-indent t 3) #f))
(define (count-char text c [start 0] [end (send text last-position)])
(for*/sum ([pos (in-range start (add1 end))])
(if ((char text pos) . char=? . c)
1
0)))
(module+ test
(check-equal? (count-char t #\f) 1)
(check-equal? (count-char t #\o) 2)
(check-equal? (count-char t #\o 0 1) 1)
(check-equal? (count-char t #\newline) 2))