;;; r6rs-libraries.scm --- Support for the R6RS `library' and `import' forms
;; Copyright (C) 2010 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
;; This file is included from boot-9.scm and assumes the existence of (and
;; expands into) procedures and syntactic forms defined therein.
(define (resolve-r6rs-interface import-spec)
(define (make-custom-interface mod)
(let ((iface (make-module)))
(set-module-kind! iface 'custom-interface)
(set-module-name! iface (module-name mod))
iface))
(define (sym? x) (symbol? (syntax->datum x)))
(syntax-case import-spec (library only except prefix rename srfi)
;; (srfi :n ...) -> (srfi srfi-n ...)
((library (srfi colon-n rest ... (version ...)))
(and (and-map sym? #'(srfi rest ...))
(symbol? (syntax->datum #'colon-n))
(eqv? (string-ref (symbol->string (syntax->datum #'colon-n)) 0) #\:))
(let ((srfi-n (string->symbol
(string-append
"srfi-"
(substring (symbol->string (syntax->datum #'colon-n))
1)))))
(resolve-r6rs-interface
(syntax-case #'(rest ...) ()
(()
#`(library (srfi #,srfi-n (version ...))))
((name rest ...)
;; SRFI 97 says that the first identifier after the colon-n
;; is used for the libraries name, so it must be ignored.
#`(library (srfi #,srfi-n rest ... (version ...))))))))
((library (name name* ... (version ...)))
(and-map sym? #'(name name* ...))
(resolve-interface (syntax->datum #'(name name* ...))
#:version (syntax->datum #'(version ...))))
((library (name name* ...))
(and-map sym? #'(name name* ...))
(resolve-r6rs-interface #'(library (name name* ... ()))))
((only import-set identifier ...)
(and-map sym? #'(identifier ...))
(let* ((mod (resolve-r6rs-interface #'import-set))
(iface (make-custom-interface mod)))
(for-each (lambda (sym)
(module-add! iface sym
(or (module-local-variable mod sym)
(error "no binding `~A' in module ~A"
sym mod))))
(syntax->datum #'(identifier ...)))
iface))
((except import-set identifier ...)
(and-map sym? #'(identifier ...))
(let* ((mod (resolve-r6rs-interface #'import-set))
(iface (make-custom-interface mod)))
(module-for-each (lambda (sym var) (module-add! iface sym var)) mod)
(for-each (lambda (sym)
(if (module-local-variable iface sym)
(module-remove! iface sym)
(error "no binding `~A' in module ~A" sym mod)))
(syntax->datum #'(identifier ...)))
iface))
((prefix import-set identifier)
(sym? #'identifier)
(let* ((mod (resolve-r6rs-interface #'import-set))
(iface (make-custom-interface mod))
(pre (syntax->datum #'identifier)))
(module-for-each (lambda (sym var)
(module-add! iface (symbol-append pre sym) var))
mod)
iface))
((rename import-set (from to) ...)
(and (and-map sym? #'(from ...)) (and-map sym? #'(to ...)))
(let* ((mod (resolve-r6rs-interface #'import-set))
(iface (make-custom-interface mod)))
(module-for-each (lambda (sym var) (module-add! iface sym var)) mod)
(let lp ((in (syntax->datum #'((from . to) ...))) (out '()))
(cond
((null? in)
(for-each
(lambda (pair)
(if (module-local-variable iface (car pair))
(error "duplicate binding for `~A' in module ~A"
(car pair) mod)
(module-add! iface (car pair) (cdr pair))))
out)
iface)
(else
(let ((var (or (module-local-variable mod (caar in))
(error "no binding `~A' in module ~A"
(caar in) mod))))
(module-remove! iface (caar in))
(lp (cdr in) (acons (cdar in) var out))))))))
((name name* ... (version ...))
(and-map sym? #'(name name* ...))
(resolve-r6rs-interface #'(library (name name* ... (version ...)))))
((name name* ...)
(and-map sym? #'(name name* ...))
(resolve-r6rs-interface #'(library (name name* ... ()))))))
(define-syntax library
(lambda (stx)
(define (compute-exports ifaces specs)
(define (re-export? sym)
(or-map (lambda (iface) (module-local-variable iface sym)) ifaces))
(define (replace? sym)
(module-local-variable the-scm-module sym))
(let lp ((specs specs) (e '()) (r '()) (x '()))
(syntax-case specs (rename)
(() (values e r x))
(((rename (from to) ...) . rest)
(and (and-map identifier? #'(from ...))
(and-map identifier? #'(to ...)))
(let lp2 ((in #'((from . to) ...)) (e e) (r r) (x x))
(syntax-case in ()
(() (lp #'rest e r x))
(((from . to) . in)
(cond
((re-export? (syntax->datum #'from))
(lp2 #'in e (cons #'(from . to) r) x))
((replace? (syntax->datum #'from))
(lp2 #'in e r (cons #'(from . to) x)))
(else
(lp2 #'in (cons #'(from . to) e) r x)))))))
((id . rest)
(identifier? #'id)
(let ((sym (syntax->datum #'id)))
(cond
((re-export? sym)
(lp #'rest e (cons #'id r) x))
((replace? sym)
(lp #'rest e r (cons #'id x)))
(else
(lp #'rest (cons #'id e) r x))))))))
(syntax-case stx (export import)
((_ (name name* ...)
(export espec ...)
(import ispec ...)
body ...)
(and-map identifier? #'(name name* ...))
;; Add () as the version.
#'(library (name name* ... ())
(export espec ...)
(import ispec ...)
body ...))
((_ (name name* ... (version ...))
(export espec ...)
(import ispec ...)
body ...)
(and-map identifier? #'(name name* ...))
(call-with-values
(lambda ()
(compute-exports
(map (lambda (im)
(syntax-case im (for)
((for import-set import-level ...)
(resolve-r6rs-interface #'import-set))
(import-set (resolve-r6rs-interface #'import-set))))
#'(ispec ...))
#'(espec ...)))
(lambda (exports re-exports replacements)
(with-syntax (((e ...) exports)
((r ...) re-exports)
((x ...) replacements))
;; It would be nice to push the module that was current before the
;; definition, and pop it after the library definition, but I
;; actually can't see a way to do that. Helper procedures perhaps,
;; around a fluid that is rebound in save-module-excursion? Patches
;; welcome!
#'(begin
(define-module (name name* ...)
#:pure
#:version (version ...))
(import ispec)
...
(export e ...)
(re-export r ...)
(export! x ...)
(@@ @@ (name name* ...) body)
...))))))))
(define-syntax import
(lambda (stx)
(define (strip-for import-set)
(syntax-case import-set (for)
((for import-set import-level ...)
#'import-set)
(import-set
#'import-set)))
(syntax-case stx ()
((_ import-set ...)
(with-syntax (((library-reference ...) (map strip-for #'(import-set ...))))
#'(eval-when (expand load eval)
(let ((iface (resolve-r6rs-interface 'library-reference)))
(call-with-deferred-observers
(lambda ()
(module-use-interfaces! (current-module) (list iface)))))
...
(if #f #f)))))))