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; From Eli Barzilay, eli@barzilay.org
;> (require "brackets.scm")
;> (use-bracket-readtable)
;> ([+ _ 1] 10)
;11
(module brackets mzscheme
; main reader function for []s
; recursive read starts with default readtable's [ parser,
; but nested reads still use the curent readtable:
(define (read-square-brackets ch port src line col pos)
`(fn (_)
,(read/recursive port #\[ #f)))
; a readtable that is just like the builtin except for []s
(define bracket-readtable
(make-readtable #f #\[ 'terminating-macro read-square-brackets))
; call this to set the global readtable
(provide use-bracket-readtable)
(define (use-bracket-readtable)
(current-readtable bracket-readtable))
; these two implement the required functionality for #reader
;(define (*read inp)
; (parameterize ((current-readtable bracket-readtable))
; (read inp)))
(define (*read . args)
(parameterize ((current-readtable bracket-readtable))
(read (if (null? args) (current-input-port) (car args)))))
(define (*read-syntax src port)
(parameterize ((current-readtable bracket-readtable))
(read-syntax src port)))
; and the need to be provided as `read' and `read-syntax'
(provide (rename *read read) (rename *read-syntax read-syntax))
)
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