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(define-library (zambyte meta json)
;; portable
(export json
define-json-record-type
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))
(cond-expand
(gerbil (import (std srfi 1)
(only (gerbil core) and-let*)))
(else (import (srfi 1)
(srfi 2))))
;; 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 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
(internal-json-record fields ...)
internal-json-record?
field-declarations ...)
(define-syntax accessors
(syntax-rules ::: ()
((_) '())
((_ (name accessor . optional-mutator) rest :::)
(cons `(name . ,accessor) (accessors rest :::)))))
(define-syntax mutators
(syntax-rules ::: ()
((_) '())
((_ (name accessor) rest :::)
(mutators rest :::))
((_ (name accessor mutator) rest :::)
(cons `(name . ,mutator) (mutators rest :::)))))
(define (constructor fields ...)
(define (typeless)
(json-object `(fields . ,fields) ...))
(json-record (internal-json-record fields ...)
'type
typeless
(accessors field-declarations ...)
(mutators field-declarations ...)))
(define (predicate obj)
(cond
((json-record? obj) (internal-json-record?
(json-record->internal-record 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)
;; Assume that json-key-not-found is set to something sensible
(constructor (json-object-ref json 'fields) ...)
(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))))
(define-syntax define-accessors-and-mutators
(syntax-rules ::: ()
((_) (values))
((_ (name accessor) rest :::)
(begin
(define (accessor json)
(if (json-record? json)
(or (and-let* ((pair (assoc 'name (json-record->accessors json)))
(acc (cdr pair)))
(acc (json-record->internal-record json)))
(error (string-append (symbol->string 'accessor) ": no accessor for field") (json-record->name json) 'name))
(json-object-ref json 'name)))
(define-accessors-and-mutators rest :::)))
((_ (name accessor mutator) rest :::)
(begin
(define (accessor json)
(if (json-record? json)
(or (and-let* ((pair (assoc 'name (json-record->accessors json)))
(acc (cdr pair)))
(acc (json-record->internal-record json)))
(error (string-append (symbol->string 'accessor) ": no accessor for field") (json-record->name json) 'name))
(json-object-ref json 'name)))
(define (mutator json value)
(if (json-record? json)
(or (and-let* ((pair (assoc 'name (json-record->mutators json)))
(mut! (cdr pair)))
(mut! (json-record->internal-record json) value))
(error (string-append (symbol->string 'mutator) ": no mutator for field") (json-record->name json) 'name))
(json-object-set! json 'name value)))
(define-accessors-and-mutators rest :::)))))
(define-accessors-and-mutators field-declarations ...)))))
(define-record-type <json-record>
(json-record internal-record name typeless accessors mutators)
json-record?
(internal-record json-record->internal-record)
(name json-record->name)
(typeless json-record->typeless)
(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->typeless 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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