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48 lines
1.5 KiB
Racket
48 lines
1.5 KiB
Racket
#lang debug racket/base
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(require racket/file
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racket/fasl
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"words.rkt")
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(provide (all-defined-out))
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(define (char->bitindex c)
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;; 64-bit layout
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;; __________ZYXWVUTSRQPONMLKJIHGFEDCBA______zyxwvutsrqponmlkjihgfedcba
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(cond
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[(char<=? #\a c #\z) (- (char->integer c) 97)] ; 97 = (char->integer #\a)
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[(char<=? #\A c #\Z) (- (char->integer c) 33)] ; 65 = (char->integer #\A)
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[else 0]))
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(define (word->charidx word)
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(apply bitwise-ior
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(for/list ([c (in-string word)])
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(expt 2 (char->bitindex c)))))
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(define (bitindex->char i)
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(cond
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[(<= 0 i 26) (integer->char (+ i 97))]
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[(<= 32 i 59) (integer->char (+ i 33))]
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[else (error 'bong)]))
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(define (charidx->chars int)
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(for/list ([i (in-range 64)]
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#:when (bitwise-bit-set? int i))
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(bitindex->char i)))
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(define charidx-file "data/charidx.rktd")
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(define (regenerate-char-index!)
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(s-exp->fasl (map word->charidx usable-words) (open-output-file charidx-file #:exists 'replace)))
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(define charidx (let ()
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(unless (file-exists? charidx-file)
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(regenerate-char-index!))
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(fasl->s-exp (open-input-file charidx-file))))
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(define (contains-char? charidx-entry c)
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(bitwise-bit-set? charidx-entry (char->bitindex c)))
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(module+ test
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(require rackunit)
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(check-equal? (length (filter (λ (ce) (contains-char? ce #\z)) charidx)) 7830)
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(check-equal? (charidx->chars (word->charidx "abuzz")) '(#\a #\b #\u #\z)))
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