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;;; Extensions to SRFI-9
;; Copyright (C) 2010, 2012 Free Software Foundation, Inc.
;;
;; This library is free software; you can redistribute it and/or
;; modify it under the terms of the GNU Lesser General Public
;; License as published by the Free Software Foundation; either
;; version 3 of the License, or (at your option) any later version.
;;
;; This library is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
;; Lesser General Public License for more details.
;;
;; You should have received a copy of the GNU Lesser General Public
;; License along with this library; if not, write to the Free Software
;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
;;; Commentary:
;; Extensions to SRFI-9. Fully documented in the Guile Reference Manual.
;;; Code:
(define-module (srfi srfi-9 gnu)
#:use-module (srfi srfi-1)
#:use-module (system base ck)
#:export (set-record-type-printer!
define-immutable-record-type
set-field
set-fields))
(define (set-record-type-printer! type proc)
"Set PROC as the custom printer for TYPE."
(struct-set! type vtable-index-printer proc))
(define-syntax-rule (define-immutable-record-type name ctor pred fields ...)
((@@ (srfi srfi-9) %define-record-type)
#t (define-immutable-record-type name ctor pred fields ...)
name ctor pred fields ...))
(define-syntax-rule (set-field s (getter ...) expr)
(%set-fields #t (set-field s (getter ...) expr) ()
s ((getter ...) expr)))
(define-syntax-rule (set-fields s . rest)
(%set-fields #t (set-fields s . rest) ()
s . rest))
;;
;; collate-set-field-specs is a helper for %set-fields
;; thats combines all specs with the same head together.
;;
;; For example:
;;
;; SPECS: (((a b c) expr1)
;; ((a d) expr2)
;; ((b c) expr3)
;; ((c) expr4))
;;
;; RESULT: ((a ((b c) expr1)
;; ((d) expr2))
;; (b ((c) expr3))
;; (c (() expr4)))
;;
(define (collate-set-field-specs specs)
(define (insert head tail expr result)
(cond ((find (lambda (tree)
(free-identifier=? head (car tree)))
result)
=> (lambda (tree)
`((,head (,tail ,expr)
,@(cdr tree))
,@(delq tree result))))
(else `((,head (,tail ,expr))
,@result))))
(with-syntax (((((head . tail) expr) ...) specs))
(fold insert '() #'(head ...) #'(tail ...) #'(expr ...))))
(define-syntax unknown-getter
(lambda (x)
(syntax-case x ()
((_ orig-form getter)
(syntax-violation 'set-fields "unknown getter" #'orig-form #'getter)))))
(define-syntax c-list
(lambda (x)
(syntax-case x (quote)
((_ s 'v ...)
#'(ck s '(v ...))))))
(define-syntax c-same-type-check
(lambda (x)
(syntax-case x (quote)
((_ s 'orig-form '(path ...)
'(getter0 getter ...)
'(type0 type ...)
'on-success)
(every (lambda (t g)
(or (free-identifier=? t #'type0)
(syntax-violation
'set-fields
(format #f
"\
field paths ~a and ~a require one object to belong to two different record types (~a and ~a)"
(syntax->datum #`(path ... #,g))
(syntax->datum #'(path ... getter0))
(syntax->datum t)
(syntax->datum #'type0))
#'orig-form)))
#'(type ...)
#'(getter ...))
#'(ck s 'on-success)))))
(define-syntax %set-fields
(lambda (x)
(with-syntax ((getter-type #'(@@ (srfi srfi-9) getter-type))
(getter-index #'(@@ (srfi srfi-9) getter-index))
(getter-copier #'(@@ (srfi srfi-9) getter-copier)))
(syntax-case x ()
((_ check? orig-form (path-so-far ...)
s)
#'s)
((_ check? orig-form (path-so-far ...)
s (() e))
#'e)
((_ check? orig-form (path-so-far ...)
struct-expr ((head . tail) expr) ...)
(let ((collated-specs (collate-set-field-specs
#'(((head . tail) expr) ...))))
(with-syntax (((getter0 getter ...)
(map car collated-specs)))
(with-syntax ((err #'(unknown-getter
orig-form getter0)))
#`(ck
()
(c-same-type-check
'orig-form
'(path-so-far ...)
'(getter0 getter ...)
(c-list (getter-type 'getter0 'err)
(getter-type 'getter 'err) ...)
'(let ((s struct-expr))
((ck () (getter-copier 'getter0 'err))
check?
s
#,@(map (lambda (spec)
(with-syntax (((head (tail expr) ...) spec))
(with-syntax ((err #'(unknown-getter
orig-form head)))
#'(head (%set-fields
check?
orig-form
(path-so-far ... head)
(struct-ref s (ck () (getter-index
'head 'err)))
(tail expr) ...)))))
collated-specs)))))))))
((_ check? orig-form (path-so-far ...)
s (() e) (() e*) ...)
(syntax-violation 'set-fields "duplicate field path"
#'orig-form #'(path-so-far ...)))
((_ check? orig-form (path-so-far ...)
s ((getter ...) expr) ...)
(syntax-violation 'set-fields "one field path is a prefix of another"
#'orig-form #'(path-so-far ...)))
((_ check? orig-form . rest)
(syntax-violation 'set-fields "invalid syntax" #'orig-form))))))
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