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Paste # 16845
2017-11-23 13:29:37

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make-env-param

  1. #lang racket
  2.  
  3. (define-syntax make-env-param
  4.   (syntax-rules ()
  5.     [(make-env-param id)
  6.      ;; Base case: one identifier
  7.      (define id
  8.        (make-parameter #f (lambda (a)
  9.                             (and (string-environment-variable-name? a)
  10.                                  a))))]
  11.     [(make-env-param id more ...)
  12.      ;; Recursive case: an identifier and one or more other identifiers
  13.      (begin (make-env-param id)
  14.             (make-env-param more ...))]))

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