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Paste # 65687
2017-11-17 23:37:40

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  1. #lang racket
  2.  
  3. (require syntax/parse/define)
  4.  
  5. (define-syntax-parser a
  6.   #:datum-literals (x y)
  7.   [(_ (~or x-use:x y-use:y) ...)
  8.    (displayln (attribute x-use))
  9.    (displayln (attribute y-use))
  10.    #'(void)])
  11.  
  12. (a x)
  13. (a y)

=>

(#<syntax:3:0 x>)

()

()

(#<syntax:4:0 y>)