divorce
b735900f2e
ddat interop with dat js cable interop with cabal js ddat's frontend = dat-thang cable fe = cable-thang dillo support based on cel's dillo-dat bootstrap node xplatform support Signed-off-by: divo <418@cryspace.space>
43 lines
1.8 KiB
Scheme
43 lines
1.8 KiB
Scheme
;;; Shared record conventions for Scheme-facing Dat APIs.
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;;; A record is (tag (field . value) ...); payload bytes stay bytevectors.
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(define (dat:record? value . wanted-tag)
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(and (pair? value)
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(symbol? (car value))
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(or (null? wanted-tag) (eq? (car value) (car wanted-tag)))
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(let loop ((fields (cdr value)) (seen '()))
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(if (null? fields)
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#t
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(and (pair? fields)
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(pair? (car fields))
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(symbol? (caar fields))
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(not (memq (caar fields) seen))
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(loop (cdr fields) (cons (caar fields) seen)))))))
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(define (dat:record-ref record field . fallback)
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(if (not (dat:record? record))
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(error 'wrong-type-arg "expected a Dat record" record)
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(if (not (symbol? field))
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(error 'wrong-type-arg "record field name must be a symbol" field)
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(let ((entry (assq field (cdr record))))
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(if entry
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(cdr entry)
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(if (pair? fallback) (car fallback) #f))))))
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(define (dat:record-set record field value)
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(if (not (dat:record? record))
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(error 'wrong-type-arg "expected a Dat record" record)
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(if (not (symbol? field))
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(error 'wrong-type-arg "record field name must be a symbol" field)
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(let loop ((fields (cdr record)) (reversed '()) (found #f))
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(if (null? fields)
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(cons (car record)
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(reverse (if found reversed
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(cons (cons field value) reversed))))
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(let ((entry (car fields)))
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(if (eq? (car entry) field)
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(loop (cdr fields) (cons (cons field value) reversed) #t)
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(loop (cdr fields) (cons entry reversed) found))))))))
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(provide 'dat:record)
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