48 lines
1.1 KiB
Scheme
48 lines
1.1 KiB
Scheme
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; Copyright (c) 1993-1999 by Richard Kelsey and Jonathan Rees. See file COPYING.
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(define (adjoin-bits high low k)
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(+ (shift-left high k) low))
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(define (low-bits n k)
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(bitwise-and n (- (shift-left 1 k) 1)))
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(define high-bits arithmetic-shift-right)
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(define unsigned-high-bits logical-shift-right)
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(define (digit? ch)
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(let ((ch (char->ascii ch)))
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(and (>= ch (char->ascii #\0))
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(<= ch (char->ascii #\9)))))
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(define (vector+length-fill! v length x)
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(do ((i 0 (+ i 1)))
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((>= i length))
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(vector-set! v i x)))
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; Apply PROC to 0 ... N-1.
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(define (natural-for-each proc n)
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(do ((i 0 (+ i 1)))
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((= i n))
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(proc i)))
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;----------------
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(define (error? status)
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(not (eq? status (enum errors no-errors))))
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(define (write-error-string string)
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(write-string string (current-error-port)))
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(define (write-error-integer integer)
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(write-integer integer (current-error-port)))
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(define (write-error-newline)
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(write-char #\newline (current-error-port)))
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(define (error-message string)
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(write-error-string string)
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(write-error-newline))
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