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