9e93ee2682
This ensures that `=>` and `else` have the same bindings as the ones in `racket/private/cond`; otherwise it would not be possible to use SRFI 61 `cond` from a `#lang racket/base` program/module. Tested under both `#lang racket` and `#lang mzscheme`.
31 lines
964 B
Racket
31 lines
964 B
Racket
;;SRFI 61 A more general COND clause
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;;Chongkai Zhu mrmathematica@yahoo.com
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;;12-18-2005
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;; * Updated by Chris Jester-Young 2013-02-28
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#lang racket/base
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(provide (prefix-out srfi: (combine-out cond => else)))
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(define-syntax cond
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(syntax-rules (=> else)
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((_ (else else1 else2 ...))
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(when #t (begin else1 else2 ...)))
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((_ (test => receiver) more-clause ...)
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(let ((t test))
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(if t
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(receiver t)
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(cond more-clause ...))))
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((_ (generator guard => receiver) more-clause ...)
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(call-with-values (lambda () generator)
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(lambda t
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(if (apply guard t)
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(apply receiver t)
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(cond more-clause ...)))))
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((_ (test) more-clause ...)
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(or test (cond more-clause ...)))
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((_ (test body ...) more-clause ...)
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(if test
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(begin body ...)
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(cond more-clause ...)))
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((_)
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(void))))
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