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41 lines
1.1 KiB
Scheme
41 lines
1.1 KiB
Scheme
#cs
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(module terminal-syntax mzscheme
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;; The things needed at compile time to handle definition of tokens
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(provide make-terminals-def terminals-def-t terminals-def? define-tokens-helper)
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(define-struct terminals-def (t))
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(define (define-tokens-helper stx runtime empty?)
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(syntax-case stx ()
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((_ name (terms ...))
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(andmap identifier? (syntax->list (syntax (terms ...))))
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(datum->syntax-object
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runtime
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`(begin
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(define-syntax ,(syntax name)
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(make-terminals-def ',(syntax (terms ...))))
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,@(map
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(lambda (n)
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(if (eq? (syntax-object->datum n) 'error)
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(raise-syntax-error
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#f
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"Cannot define a token named error."
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stx))
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`(define (,(datum->syntax-object
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n
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(string->symbol
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(format "token-~a" (syntax-object->datum n)))
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n)
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,@(if empty? '() '(x)))
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(make-token ',n ,(if empty? #f 'x))))
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(syntax->list (syntax (terms ...)))))
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stx))
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((_ ...)
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(raise-syntax-error
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#f
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"must have the form (define-tokens name (symbol ...))"
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stx))))
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)
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