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58 lines
1.8 KiB
Racket

#lang debug racket/base
(require racket/file
racket/fasl
racket/vector
"words.rkt")
(provide (all-defined-out))
(define (char->bitindex c)
;; 64-bit layout
;; __________ZYXWVUTSRQPONMLKJIHGFEDCBA______zyxwvutsrqponmlkjihgfedcba
(cond
[(char<=? #\a c #\z) (- (char->integer c) 97)] ; 97 = (char->integer #\a)
[(char<=? #\A c #\Z) (- (char->integer c) 33)] ; 65 = (char->integer #\A)
[else 0]))
(define (word->charidx word)
(apply bitwise-ior
(for/list ([c (in-string word)])
(expt 2 (char->bitindex c)))))
(define (bitindex->char i)
(cond
[(<= 0 i 26) (integer->char (+ i 97))]
[(<= 32 i 59) (integer->char (+ i 33))]
[else (error 'bong)]))
(define (charidx->chars int)
(for/list ([i (in-range 64)]
#:when (bitwise-bit-set? int i))
(bitindex->char i)))
(define charidx-file "compiled/charidx.rktd")
(define (regenerate-char-index!)
(s-exp->fasl (vector-map word->charidx usable-words) (open-output-file charidx-file #:exists 'replace)))
(define charidx (let ()
(unless (file-exists? charidx-file)
(regenerate-char-index!))
(fasl->s-exp (open-input-file charidx-file))))
(define (contains-char? charidx-entry c)
(bitwise-bit-set? charidx-entry (char->bitindex c)))
(define capitalized-mask
(for/sum ([i (in-range 32 59)])
(expt 2 i)))
(define (capitalized? charidx-entry)
;; a cap only appears at the beginning of a word,
;; so it's sufficient to test whether a cap exists in the idx
(positive? (bitwise-and charidx-entry capitalized-mask)))
(module+ test
(require rackunit racket/vector)
(check-equal? (vector-length (vector-filter (λ (ce) (contains-char? ce #\z)) charidx)) 7830)
(check-equal? (charidx->chars (word->charidx "abuzz")) '(#\a #\b #\u #\z)))