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(define-library (zambyte meta json)
;; portable
(export json
define-json-record-type
json->typeless-json
json-ref
json-value?
json-record-from-string-allow-missing-keys
json-key-not-found)
;; non-portable
(export json-object
json-list
json-null
json-object?
json-list?
json-null?
json-object-contains-key?
string->json
json->string
json-object-ref
json-object-set!
json-list-ref
json-list-length
json-object-map
json-list-map
json-object->alist
json-list->list)
(import (scheme base))
;; portable
(begin
(define-syntax json
(syntax-rules (object list null true false)
((_ (object (key . value) ...))
(json-object `(key . ,(json value)) ...))
((_ (list vs ...))
(json-list (json vs) ...))
((_ null) json-null)
((_ true) #t)
((_ false) #f)
((_ value)
(if (json-value? value)
value
(error "json: not a json value" value)))))
(define-syntax handle-field-declarations
(syntax-rules ()
((_ (field accessor))
(define (accessor obj)
(json-object-ref obj 'field)))
((_ (field accessor mutator))
(begin
(define (accessor obj)
(json-object-ref obj 'field))
(define (mutator obj value)
(json-object-set! (json-record->fields obj) 'field value))))))
(define-syntax get-accessor
(syntax-rules ()
((_ (field accessor rest ...))
`(field . ,accessor))))
(define-syntax get-mutator
(syntax-rules ()
((_ (field _ mutator))
`(field . ,mutator))
((_ (field _))
`(field . #f))))
(define-syntax define-json-record-type
(syntax-rules ()
((_ type
(constructor fields ...)
from-json-string
predicate
field-declarations ...)
(begin
(define-values (constructor predicate from-json-string)
((lambda ()
(define-record-type type
(make-tag)
pred?)
(define tag (make-tag))
(define (constructor fields ...)
(make-json-record 'type
tag
(json-object `(fields . ,fields) ...)
from-json-string
(list (get-accessor field-declarations) ...)
(list (get-mutator field-declarations) ...)))
(define (predicate obj)
(cond
((json-record? obj) (pred? (json-record->tag obj)))
((json-object? obj) (and (json-object-contains-key? obj 'fields) ...))
(else #f)))
(define (from-json-string str)
(let ((json (string->json str)))
(if (json-record-from-string-allow-missing-keys)
(make-json-record 'type
tag
(string->json str)
from-json-string
(list (get-accessor field-declarations) ...)
(list (get-mutator field-declarations) ...))
(parameterize ((json-key-not-found
(lambda ()
(error "key not found in json string when converting to a record" 'type))))
(constructor (json-object-ref json 'fields) ...)))))
(values constructor predicate from-json-string))))
(handle-field-declarations field-declarations) ...))))
(define-record-type <json-record>
(make-json-record name tag fields from-json-string accessors mutators)
json-record?
(name json-record->name)
(tag json-record->tag)
(fields json-record->fields)
(from-json-string json-record->from-json-string)
(accessors json-record->accessors)
(mutators json-record->mutators))
(define json-record-from-string-allow-missing-keys (make-parameter #f))
(define (json->typeless-json json)
(cond
((json-record? json)
(json->typeless-json (json-record->fields json)))
((json-object? json)
(json-object-map (lambda (k v) (values k (json->typeless-json v))) json))
((json-list? json)
(json-list-map (lambda (v) (json->typeless-json v)) json))
(else json)))
(define (json-ref json key . keys)
(let ((ref (cond ((json-object? json) json-object-ref)
((json-list? json) json-list-ref)
(else (error "json-ref: cannot get reference on json value" json)))))
(if (null? keys)
(ref json key)
(apply json-ref (ref json key) keys))))
(define (json-value? obj)
(or (boolean? obj)
(number? obj)
(string? obj)
(json-null? obj)
(json-list? obj)
(json-object? obj)))
(define json-key-not-found (make-parameter (lambda () (values)))))
;; non-portable
(cond-expand
((and (library (macduffie json)) (library (srfi 69)))
(include-library-declarations "macduffie.scm"))
((and guile (library (json)))
(import (only (guile) include-from-path import))
(begin (include-from-path "zambyte/meta/guile-json.scm")))
(gauche
(include-library-declarations "gauche.scm"))
(gerbil
(include-library-declarations "gerbil.scm"))
(sagittarius
(include-library-declarations "sagittarius.scm"))
((library (chibi json))
(include-library-declarations "chibi.scm"))
((library (srfi 180))
(include-library-declarations "180.scm"))
(else
(error "No implementation of JSON library available."))))
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