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;; JSON implementation for Scheme
;; See http://www.json.org/ or http://www.crockford.com/JSON/index.html
;;
;; Copyright (c) 2005 Tony Garnock-Jones <tonyg@kcbbs.gen.nz>
;; Copyright (c) 2005 LShift Ltd. <query@lshift.net>
;;
;; Permission is hereby granted, free of charge, to any person
;; obtaining a copy of this software and associated documentation
;; files (the "Software"), to deal in the Software without
;; restriction, including without limitation the rights to use, copy,
;; modify, merge, publish, distribute, sublicense, and/or sell copies
;; of the Software, and to permit persons to whom the Software is
;; furnished to do so, subject to the following conditions:
;;
;; The above copyright notice and this permission notice shall be
;; included in all copies or substantial portions of the Software.
;;
;; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
;; EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
;; MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
;; NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
;; BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
;; ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
;; CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
;; SOFTWARE.
;; JSON Structures are represented as vectors: #((symbol . value) (symbol . value) ...)
;; JSON Arrays are lists
;;
(require-extension (srfi 69))
(require "packrat.scm")
(require "json-parser-expanded.scm")
(define (hashtable->vector ht)
(list->vector (hash-table->alist ht)) )
(define json-write
(let ()
(define (write-ht vec p)
(display "{" p)
(do ((need-comma #f #t)
(i 0 (+ i 1)))
((= i (vector-length vec)))
(if need-comma
(display ", " p)
(set! need-comma #t))
(let* ((entry (vector-ref vec i))
(k (car entry))
(v (cdr entry)))
(cond
((symbol? k) (write (symbol->string k) p))
((string? k) (write k p)) ;; for convenience
(else (error "Invalid JSON table key in json-write" k)))
(display ": " p)
(write-any v p)))
(display "}" p))
(define (write-array a p)
(display "[" p)
(let ((need-comma #f))
(for-each (lambda (v)
(if need-comma
(display ", " p)
(set! need-comma #t))
(write-any v p))
a))
(display "]" p))
(define (write-any x p)
(cond
((hash-table? x) (write-ht (hashtable->vector x) p))
((vector? x) (write-ht x p))
((list? x) (write-array x p))
((symbol? x) (write (symbol->string x) p)) ;; for convenience
((or (string? x)
(number? x)) (write x p))
((boolean? x) (display (if x "true" "false") p))
((eq? x (void)) (display "null" p))
(else (error "Invalid JSON object in json-write" x))))
(lambda (x . maybe-port)
(write-any x (if (pair? maybe-port) (car maybe-port) (current-output-port))))))
(define json-read
(let ()
(define (generator p)
(let ((ateof #f)
(pos (top-parse-position "<?>")))
(lambda ()
(if ateof
(values pos #f)
(let ((x (read-char p)))
(if (eof-object? x)
(begin
(set! ateof #t)
(values pos #f))
(let ((old-pos pos))
(set! pos (update-parse-position pos x))
(values old-pos (cons x x)))))))))
(define parser
expanded:json-parser)
(define (read-any p)
(let ((result (parser (base-generator->results (generator p)))))
(if (parse-result-successful? result)
(parse-result-semantic-value result)
(error "JSON Parse Error"
(let ((e (parse-result-error result)))
(list 'json-parse-error
(parse-position->string (parse-error-position e))
(parse-error-expected e)
(parse-error-messages e)))))))
(lambda maybe-port
(read-any (if (pair? maybe-port) (car maybe-port) (current-input-port))))))
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