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simplify `string->hashpair`

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Matthew Butterick 8 years ago
parent cf2cdb6413
commit 3c7a58445b
1 changed files with 31 additions and 26 deletions
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57
hyphenate/hyphenate/private/core.rkt
Unescape Escape View File

@ -26,35 +26,40 @@
(define (string->natural i)
(let* ([result (string->number i)]
[result (and (number? result) (inexact->exact result))]
[result (and result (inexact->exact result))]
[result (and (exact-nonnegative-integer? result) result)])
result))
(define (string->hashpair pat)
(define boundary-name ".")
;; first convert the pattern to a list of alternating letters and numbers.
;; insert zeroes where there isn't a number in the pattern.
(define new-pat
(let* ([pat (regexp-match* #rx"." pat)] ; convert to list
[pat (map (λ(i) (or (string->natural i) i)) pat)] ; convert numbers
[pat (if (string? (car pat)) (cons 0 pat) pat)] ; add zeroes to front where needed
[pat (if (string? (car (reverse pat))) (reverse (cons 0 (reverse pat))) pat)]) ; and back
(apply append
(reverse (for/fold([acc null])
([current (in-list pat)][i (in-naturals)])
(if (= i (sub1 (length pat)))
(cons (reverse (list current)) acc)
(let ([next (list-ref pat (add1 i))])
;; insert zeroes where there isn't a number
(cons (reverse (if (and (or (equal? current boundary-name) (string? current)) (string? next))
(list current 0)
(list current))) acc))))))))
;; then slice out the string & numerical parts to be a key / value pair.
(define value (filter exact-nonnegative-integer? new-pat))
(define key (filter string? new-pat))
(list (apply string-append key) value))
(define-values (strs nums)
(for/lists (strs nums)
;; using unicode-aware regexps to allow unicode hyphenation patterns
([subpat (in-list (regexp-match* #px"^\\d?|(\\p{L}|\\p{P})\\d?" pat))])
(define str (cond
[(regexp-match #px"(\\p{L}|\\p{P})?" subpat) => car]
[else ""]))
(define num (cond
[(regexp-match #px"\\d" subpat) => (compose1 string->natural car)]
[else 0]))
(values str num)))
(list (string-append* strs) nums))
(module+ test
(require rackunit)
(check-equal? (string->hashpair "2'2") '("'" (2 2)))
(check-equal? (string->hashpair ".â4") '(".â" (0 0 4)))
(check-equal? (string->hashpair ".ý4") '(".ý" (0 0 4)))
(check-equal? (string->hashpair "'ý4") '("'ý" (0 0 4)))
(check-equal? (string->hashpair "’ý4") '("’ý" (0 0 4)))
(check-equal? (string->hashpair "4ý-") '("ý-" (4 0 0)))
(check-equal? (string->hashpair ".ach4") '(".ach" (0 0 0 0 4)))
(check-equal? (string->hashpair ".ad4der") '(".adder" (0 0 0 4 0 0 0)))
(check-equal? (string->hashpair ".af1t") '(".aft" (0 0 0 1 0)))
(check-equal? (string->hashpair ".al3t") '(".alt" (0 0 0 3 0))))
(define (make-points word)
;; walk through all the substrings and see if there's a matching pattern.
@ -101,9 +106,9 @@
;; Find hyphenation points in a word. This is not quite synonymous with syllables.
(define (word->hyphenation-points word
[min-length default-min-length]
[min-left-length default-min-left-length]
[min-right-length default-min-right-length])
[min-length default-min-length]
[min-left-length default-min-left-length]
[min-right-length default-min-right-length])
#;((string?) ((or/c #f exact-nonnegative-integer?)(or/c #f exact-nonnegative-integer?)(or/c #f exact-nonnegative-integer?)) . ->* . (listof string?))
(define (add-no-hyphen-zone points)
;; points is a list corresponding to the letters of the word.

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