picrin/piclib/picrin/record.scm

110 lines
3.5 KiB
Scheme

(define-library (picrin record)
(import (picrin base)
(picrin macro))
;; define-record-writer
(define (set-record-writer! record-type writer)
(record-set! record-type 'writer writer))
(define-syntax define-record-writer
(er-macro-transformer
(lambda (form r compare)
(let ((formal (cadr form)))
(if (pair? formal)
`(,(r 'set-record-writer!) ,(car formal)
(,(r 'lambda) (,(cadr formal))
,@(cddr form)))
`(,(r 'set-record-writer!) ,formal
,@(cddr form)))))))
;; define-record-type
(define ((default-record-writer ctor) obj)
(let ((port (open-output-string)))
(display "#.(" port)
(display (car ctor) port)
(for-each
(lambda (field)
(display " " port)
(write (record-ref obj field) port))
(cdr ctor))
(display ")" port)
(get-output-string port)))
(define ((boot-make-record-type <meta-type>) name ctor)
(let ((rectype (make-record <meta-type>)))
(record-set! rectype 'name name)
(record-set! rectype 'writer (default-record-writer ctor))
rectype))
(define <record-type>
(let ((<record-type>
((boot-make-record-type #t) 'record-type '(record-type name writer))))
(record-set! <record-type> '@@type <record-type>)
<record-type>))
(define make-record-type (boot-make-record-type <record-type>))
(define-syntax define-record-constructor
(ir-macro-transformer
(lambda (form inject compare?)
(let ((rectype (car (cdr form)))
(name (car (cdr (cdr form))))
(fields (cdr (cdr (cdr form)))))
`(define (,name ,@fields)
(let ((record (make-record ,rectype)))
,@(map (lambda (field)
`(record-set! record ',field ,field))
fields)
record))))))
(define-syntax define-record-predicate
(ir-macro-transformer
(lambda (form inject compare?)
(let ((rectype (car (cdr form)))
(name (car (cdr (cdr form)))))
`(define (,name obj)
(and (record? obj)
(eq? (record-type obj)
,rectype)))))))
(define-syntax define-record-field
(ir-macro-transformer
(lambda (form inject compare?)
(let ((pred (car (cdr form)))
(field-name (car (cdr (cdr form))))
(accessor (car (cdr (cdr (cdr form)))))
(modifier? (cdr (cdr (cdr (cdr form))))))
(if (null? modifier?)
`(define (,accessor record)
(if (,pred record)
(record-ref record ',field-name)
(error (string-append (symbol->string ',accessor) ": wrong record type") record)))
`(begin
(define (,accessor record)
(if (,pred record)
(record-ref record ',field-name)
(error (string-append (symbol->string ',accessor) ": wrong record type") record)))
(define (,(car modifier?) record val)
(if (,pred record)
(record-set! record ',field-name val)
(error (string-append (symbol->string ',(car modifier?)) ": wrong record type") record)))))))))
(define-syntax define-record-type
(ir-macro-transformer
(lambda (form inject compare?)
(let ((name (car (cdr form)))
(ctor (car (cdr (cdr form))))
(pred (car (cdr (cdr (cdr form)))))
(fields (cdr (cdr (cdr (cdr form))))))
`(begin
(define ,name (make-record-type ',name ',ctor))
(define-record-constructor ,name ,@ctor)
(define-record-predicate ,name ,pred)
,@(map (lambda (field) `(define-record-field ,pred ,@field))
fields))))))
(export define-record-type
define-record-writer))