forked from alex-eg/sex
51 lines
1.4 KiB
Scheme
51 lines
1.4 KiB
Scheme
(import
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scheme
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(only fmt fmt)
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(chicken base)
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(chicken plist)
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(chicken string))
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(define (cat-syms s-1 s-2)
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(fmt #f s-1 s-2))
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(define (cat sym-1 sym-2)
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(string->symbol (cat-syms sym-1 sym-2)))
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;;; The reader keeps `;' comments as (comment "...") forms so they can
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;;; be re-emitted into the generated C. In a macro body a comment
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;;; should be a call which does nothing, hence this one
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(define (comment . _)
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(void))
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(define (register-macro name arglist body)
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(put! name 'sex-macro
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`(lambda ,arglist
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;; A macro body is ordinary Scheme, evaluated at compile
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;; time. It gets `cat' for building names, and read access to
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;; the type database
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(import scheme
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(scheme base)
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(only sex-macros cat comment)
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(only types get-type-info get-fields get-underlying-type
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type-match map-fields))
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,@body)))
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(define (get-macro name)
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(eval (get name 'sex-macro)))
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(define (macro? form)
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(and (list? form)
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(symbol? (car form))
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(get (car form) 'sex-macro)))
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(define (apply-macro form)
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(assert (macro? form)
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(fmt #f (car form) " is not a macro"))
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(apply (get-macro (car form))
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(cdr form)))
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(define (defmacro form)
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(let ((arglist (car form))
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(body (cdr form)))
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(register-macro (car arglist) (cdr arglist) body)))
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