26 lines
682 B
Scheme
26 lines
682 B
Scheme
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; -*- Mode: Scheme; Syntax: Scheme; Package: Scheme; -*-
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; Copyright (c) 1993, 1994 Richard Kelsey and Jonathan Rees. See file COPYING.
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; This is file enum.scm.
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;;;; Enumerated types
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; (enumerand->name <integer> <e-type>) => a symbol
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; (name->enumerand <symbol> <e-type>) => an integer
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(define (enumerand->name e e-type)
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(vector-ref e-type e))
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(define (name->enumerand e e-type)
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(let loop ((i 0)) ;vector-posq
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(if (< i (vector-length e-type))
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(if (eq? e (vector-ref e-type i))
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i
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(loop (+ i 1)))
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#f)))
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(define (definitely-name->enumerand e e-type e-type-name)
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(or (name->enumerand e e-type)
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(error "unknown enumerand name" e-type-name e)))
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