@c -*-texinfo-*-
@c This is part of the GNU Guile Reference Manual.
-@c Copyright (C) 1996, 1997, 2000, 2001, 2002, 2003, 2004, 2007, 2008
+@c Copyright (C) 1996, 1997, 2000, 2001, 2002, 2003, 2004, 2007, 2008, 2009
@c Free Software Foundation, Inc.
@c See the file guile.texi for copying conditions.
* Module System Reflection:: Accessing module objects at run-time.
* Included Guile Modules:: Which modules come with Guile?
* Accessing Modules from C:: How to work with modules with C code.
+* R6RS Version References:: Using version numbers with modules.
@end menu
@node General Information about Modules
installation directories of Guile and in all other directories in the
load path.
+A slightly different search mechanism is used when a client module
+specifies a version reference as part of a request to load a module
+(@pxref{R6RS Version References}). Instead of searching the directories
+in the load path for a single filename, Guile uses the elements of the
+version reference to locate matching, numbered subdirectories of a
+constructed base path. For example, a request for the
+@code{(rnrs base)} module with version reference @code{(6)} would cause
+Guile to discover the @code{rnrs/6} subdirectory (if it exists in any of
+the directories in the load path) and search its contents for the
+filename @code{base.scm}.
+
+When multiple modules are found that match a version reference, Guile
+sorts these modules by version number, followed by the length of their
+version specifications, in order to choose a ``best'' match.
+
@c FIXME::martin: Not sure about this, maybe someone knows better?
Every module has a so-called syntax transformer associated with it.
This is a procedure which performs all syntax transformation for the
clause is omitted, @var{renamer} operates on the used module's public
interface.
+In addition to the above, @var{spec} can also include a @code{:version}
+clause, of the form:
+
+@lisp
+ :version VERSION-SPEC
+@end lisp
+
+where @var{version-spec} is an R6RS-compatible version reference. The
+presence of this clause changes Guile's search behavior as described in
+the section on module name resolution
+(@pxref{General Information about Modules}). An error will be signaled
+in the case in which a module with the same name has already been
+loaded, if that module specifies a version and that version is not
+compatible with @var{version-spec}.
+
Signal error if module name is not resolvable.
@end deffn
The @code{#:duplicates} (see below) provides fine-grain control about
duplicate binding handling on the module-user side.
+@item #:version @var{list}
+@cindex module version
+Specify a version for the module in the form of @var{list}, a list of
+zero or more exact, nonnegative integers. The corresponding
+@code{#:version} option in the @code{use-modules} form allows callers
+to restrict the value of this option in various ways.
+
@item #:duplicates @var{list}
@cindex duplicate binding handlers
@cindex duplicate binding
@code{NULL}.
@end deftypefn
+
+@node R6RS Version References
+@subsubsection R6RS Version References
+
+Guile's module system includes support for locating modules based on
+a declared version specifier of the same form as the one described in
+R6RS (@pxref{Library form, R6RS Library Form,, r6rs, The Revised^6
+Report on the Algorithmic Language Scheme}). By using the
+@code{#:version} keyword in a @code{define-module} form, a module may
+specify a version as a list of zero or more exact, nonnegative integers.
+
+This version can then be used to locate the module during the module
+search process. Client modules and callers of the @code{use-modules}
+function may specify constraints on the versions of target modules by
+providing a @dfn{version reference}, which has one of the following
+forms:
+
+@lisp
+ (@var{sub-version-reference} ...)
+ (and @var{version-reference} ...)
+ (or @var{version-reference} ...)
+ (not @var{version-reference})
+@end lisp
+
+in which @var{sub-version-reference} is in turn one of:
+
+@lisp
+ (@var{sub-version})
+ (>= @var{sub-version})
+ (<= @var{sub-version})
+ (and @var{sub-version-reference} ...)
+ (or @var{sub-version-reference} ...)
+ (not @var{sub-version-reference})
+@end lisp
+
+in which @var{sub-version} is an exact, nonnegative integer as above. A
+version reference matches a declared module version if each element of
+the version reference matches a corresponding element of the module
+version, according to the following rules:
+
+@itemize @bullet
+@item
+The @code{and} sub-form matches a version or version element if every
+element in the tail of the sub-form matches the specified version or
+version element.
+
+@item
+The @code{or} sub-form matches a version or version element if any
+element in the tail of the sub-form matches the specified version or
+version element.
+
+@item
+The @code{not} sub-form matches a version or version element if the tail
+of the sub-form does not match the version or version element.
+
+@item
+The @code{>=} sub-form matches a version element if the element is
+greater than or equal to the @var{sub-version} in the tail of the
+sub-form.
+
+@item
+The @code{<=} sub-form matches a version element if the version is less
+than or equal to the @var{sub-version} in the tail of the sub-form.
+
+@item
+A @var{sub-version} matches a version element if one is @var{eqv?} to
+the other.
+@end itemize
+
+For example, a module declared as:
+
+@lisp
+ (define-module (mylib mymodule) #:version (1 2 0))
+@end lisp
+
+would be successfully loaded by any of the following @code{use-modules}
+expressions:
+
+@lisp
+ (use-modules ((mylib mymodule) #:version (1 2 (>= 0))))
+ (use-modules ((mylib mymodule) #:version (or (1 2 0) (1 2 1))))
+ (use-modules ((mylib mymodule) #:version ((and (>= 1) (not 2)) 2 0)))
+@end lisp
+
+
@node Dynamic Libraries
@subsection Dynamic Libraries
(make-record-type 'module
'(obarray uses binder eval-closure transformer name kind
duplicates-handlers import-obarray
- observers weak-observers)
+ observers weak-observers version)
%print-module))
;; make-module &opt size uses binder
#f #f #f
(make-hash-table %default-import-size)
'()
- (make-weak-key-hash-table 31))))
+ (make-weak-key-hash-table 31) #f)))
;; We can't pass this as an argument to module-constructor,
;; because we need it to close over a pointer to the module
;; (define module-transformer (record-accessor module-type 'transformer))
(define set-module-transformer! (record-modifier module-type 'transformer))
+(define module-version (record-accessor module-type 'version))
+(define set-module-version! (record-modifier module-type 'version))
;; (define module-name (record-accessor module-type 'name)) wait until mods are booted
(define set-module-name! (record-modifier module-type 'name))
(define module-kind (record-accessor module-type 'kind))
(eq? interface module))
(let ((interface (make-module 31)))
(set-module-name! interface (module-name module))
+ (set-module-version! interface (module-version module))
(set-module-kind! interface 'interface)
(set-module-public-interface! module interface))))
(if (and (not (memq the-scm-module (module-uses module)))
;; Import the default set of bindings (from the SCM module) in MODULE.
(module-use! module the-scm-module)))
+(define (version-matches? version-ref target)
+ (define (any pred lst)
+ (and (not (null? lst)) (or (pred (car lst)) (any pred (cdr lst)))))
+ (define (every pred lst)
+ (or (null? lst) (and (pred (car lst)) (every pred (cdr lst)))))
+ (define (sub-versions-match? v-refs t)
+ (define (sub-version-matches? v-ref t)
+ (define (curried-sub-version-matches? v)
+ (sub-version-matches? v t))
+ (cond ((number? v-ref) (eqv? v-ref t))
+ ((list? v-ref)
+ (let ((cv (car v-ref)))
+ (cond ((eq? cv '>=) (>= t (cadr v-ref)))
+ ((eq? cv '<=) (<= t (cadr v-ref)))
+ ((eq? cv 'and)
+ (every curried-sub-version-matches? (cdr v-ref)))
+ ((eq? cv 'or)
+ (any curried-sub-version-matches? (cdr v-ref)))
+ ((eq? cv 'not) (not (sub-version-matches? (cadr v-ref) t)))
+ (else (error "Incompatible sub-version reference" cv)))))
+ (else (error "Incompatible sub-version reference" v-ref))))
+ (or (null? v-refs)
+ (and (not (null? t))
+ (sub-version-matches? (car v-refs) (car t))
+ (sub-versions-match? (cdr v-refs) (cdr t)))))
+ (define (curried-version-matches? v)
+ (version-matches? v target))
+ (or (null? version-ref)
+ (let ((cv (car version-ref)))
+ (cond ((eq? cv 'and) (every curried-version-matches? (cdr version-ref)))
+ ((eq? cv 'or) (any curried-version-matches? (cdr version-ref)))
+ ((eq? cv 'not) (not version-matches? (cadr version-ref) target))
+ (else (sub-versions-match? version-ref target))))))
+
+(define (find-versioned-module dir-hint name version-ref roots)
+ (define (subdir-pair-less pair1 pair2)
+ (define (numlist-less lst1 lst2)
+ (or (null? lst2)
+ (and (not (null? lst1))
+ (cond ((> (car lst1) (car lst2)) #t)
+ ((< (car lst1) (car lst2)) #f)
+ (else (numlist-less (cdr lst1) (cdr lst2)))))))
+ (numlist-less (car pair1) (car pair2)))
+ (define (match-version-and-file pair)
+ (and (version-matches? version-ref (car pair))
+ (let ((filenames
+ (filter (lambda (file)
+ (let ((s (false-if-exception (stat file))))
+ (and s (eq? (stat:type s) 'regular))))
+ (map (lambda (ext)
+ (string-append (cdr pair) "/" name ext))
+ %load-extensions))))
+ (and (not (null? filenames))
+ (cons (car pair) (car filenames))))))
+
+ (define (match-version-recursive root-pairs leaf-pairs)
+ (define (filter-subdirs root-pairs ret)
+ (define (filter-subdir root-pair dstrm subdir-pairs)
+ (let ((entry (readdir dstrm)))
+ (if (eof-object? entry)
+ subdir-pairs
+ (let* ((subdir (string-append (cdr root-pair) "/" entry))
+ (num (string->number entry))
+ (num (and num (append (car root-pair) (list num)))))
+ (if (and num (eq? (stat:type (stat subdir)) 'directory))
+ (filter-subdir
+ root-pair dstrm (cons (cons num subdir) subdir-pairs))
+ (filter-subdir root-pair dstrm subdir-pairs))))))
+
+ (or (and (null? root-pairs) ret)
+ (let* ((rp (car root-pairs))
+ (dstrm (false-if-exception (opendir (cdr rp)))))
+ (if dstrm
+ (let ((subdir-pairs (filter-subdir rp dstrm '())))
+ (closedir dstrm)
+ (filter-subdirs (cdr root-pairs)
+ (or (and (null? subdir-pairs) ret)
+ (append ret subdir-pairs))))
+ (filter-subdirs (cdr root-pairs) ret)))))
+
+ (or (and (null? root-pairs) leaf-pairs)
+ (let ((matching-subdir-pairs (filter-subdirs root-pairs '())))
+ (match-version-recursive
+ matching-subdir-pairs
+ (append leaf-pairs (filter pair? (map match-version-and-file
+ matching-subdir-pairs)))))))
+ (define (make-root-pair root)
+ (cons '() (string-append root "/" dir-hint)))
+
+ (let* ((root-pairs (map make-root-pair roots))
+ (matches (if (null? version-ref)
+ (filter pair? (map match-version-and-file root-pairs))
+ '()))
+ (matches (append matches (match-version-recursive root-pairs '()))))
+ (and (null? matches) (error "No matching modules found."))
+ (cdar (sort matches subdir-pair-less))))
+
(define (make-fresh-user-module)
(let ((m (make-module)))
(beautify-user-module! m)
;;
(define resolve-module
(let ((the-root-module the-root-module))
- (lambda (name . maybe-autoload)
+ (lambda (name . args)
(if (equal? name '(guile))
the-root-module
(let ((full-name (append '(%app modules) name)))
- (let ((already (nested-ref the-root-module full-name))
- (autoload (or (null? maybe-autoload) (car maybe-autoload))))
+ (let* ((already (nested-ref the-root-module full-name))
+ (numargs (length args))
+ (autoload (or (= numargs 0) (car args)))
+ (version (and (> numargs 1) (cadr args))))
(cond
((and already (module? already)
(or (not autoload) (module-public-interface already)))
;; A hit, a palpable hit.
+ (if (and version
+ (not (version-matches? version (module-version already))))
+ (error "incompatible module version already loaded" name))
already)
(autoload
;; Try to autoload the module, and recurse.
- (try-load-module name)
+ (try-load-module name version)
(resolve-module name #f))
(else
;; A module is not bound (but maybe something else is),
;; (define-special-value '(%app modules new-ws) (lambda () (make-scm-module)))
-(define (try-load-module name)
- (try-module-autoload name))
+(define (try-load-module name version)
+ (try-module-autoload name version))
(define (purify-module! module)
"Removes bindings in MODULE which are inherited from the (guile) module."
(let ((prefix (get-keyword-arg args #:prefix #f)))
(and prefix (symbol-prefix-proc prefix)))
identity))
- (module (resolve-module name))
+ (version (get-keyword-arg args #:version #f))
+ (module (resolve-module name #t version))
(public-i (and module (module-public-interface module))))
(and (or (not module) (not public-i))
(error "no code for module" name))
(purify-module! module)
(loop (cdr kws) reversed-interfaces exports re-exports
replacements autoloads))
+ ((#:version)
+ (or (pair? (cdr kws))
+ (unrecognized kws))
+ (let ((version (cadr kws)))
+ (set-module-version! module version)
+ (set-module-version! (module-public-interface module) version))
+ (loop (cddr kws) reversed-interfaces exports re-exports
+ replacements autoloads))
((#:duplicates)
(if (not (pair? (cdr kws)))
(unrecognized kws))
(set-car! autoload i)))
(module-local-variable i sym))))))
(module-constructor (make-hash-table 0) '() b #f #f name 'autoload #f
- (make-hash-table 0) '() (make-weak-value-hash-table 31))))
+ (make-hash-table 0) '() (make-weak-value-hash-table 31) #f)))
(define (module-autoload! module . args)
"Have @var{module} automatically load the module named @var{name} when one
;; This function is called from "modules.c". If you change it, be
;; sure to update "modules.c" as well.
-(define (try-module-autoload module-name)
+(define (try-module-autoload module-name . args)
(let* ((reverse-name (reverse module-name))
(name (symbol->string (car reverse-name)))
+ (version (and (not (null? args)) (car args)))
(dir-hint-module-name (reverse (cdr reverse-name)))
(dir-hint (apply string-append
(map (lambda (elt)
(lambda ()
(save-module-excursion
(lambda ()
- (primitive-load-path (in-vicinity dir-hint name) #f)
+ (if version
+ (load (find-versioned-module
+ dir-hint name version %load-path))
+ (primitive-load-path (in-vicinity dir-hint name) #f))
(set! didit #t))))))
(lambda () (set-autoloaded! dir-hint name didit)))
didit))))
'((:select #:select #t)
(:hide #:hide #t)
(:prefix #:prefix #t)
- (:renamer #:renamer #f)))
+ (:renamer #:renamer #f)
+ (:version #:version #t)))
(if (not (pair? (car spec)))
`(',spec)
`(',(car spec)
HCoop / bpt / guile.git / commitdiff