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01/02: gnu: Add find-package-binding.
From: |
Andy Wingo |
Subject: |
01/02: gnu: Add find-package-binding. |
Date: |
Thu, 13 Apr 2017 07:09:19 -0400 (EDT) |
wingo pushed a commit to branch wip-potluck
in repository guix.
commit aba78aff09822cf629db9b8f03c228fda6465829
Author: Andy Wingo <address@hidden>
Date: Thu Apr 13 11:04:42 2017 +0200
gnu: Add find-package-binding.
* gnu/packages.scm (find-package-binding): New export.
---
gnu/packages.scm | 62 +++++++++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 61 insertions(+), 1 deletion(-)
diff --git a/gnu/packages.scm b/gnu/packages.scm
index 92bab72..5e85d3d 100644
--- a/gnu/packages.scm
+++ b/gnu/packages.scm
@@ -55,7 +55,9 @@
find-newest-available-packages
specification->package
- specification->package+output))
+ specification->package+output
+
+ find-package-binding))
;;; Commentary:
;;;
@@ -368,3 +370,61 @@ version; if SPEC does not specify an output, return
OUTPUT."
(leave (_ "package `~a' lacks output `~a'~%")
(package-full-name package)
sub-drv))))))
+
+(define (find-package-binding package)
+ "Find the module that exports PACKAGE. Return two values, an interface name
+and a symbol that can be used to import PACKAGE. Signal an error if no public
variable binds PACKAGE."
+ (define (strip-extension file exts)
+ (or (or-map (lambda (ext)
+ (and (string-suffix? ext file)
+ (substring file 0 (- (string-length file)
+ (string-length ext)))))
+ exts)
+ file))
+ (define (file-name->module-name file)
+ (and (not (absolute-file-name? file))
+ (map string->symbol
+ (string-split (strip-extension file %load-extensions)
+ #\/))))
+ ;; Instead of building a table and always doing a search, first just see if
+ ;; we can use the package's location to find its module and look in that
+ ;; module.
+ (define (global-search)
+ (let search ((modules (all-package-modules)))
+ (match modules
+ (()
+ (raise (condition
+ (&message (message
+ (format #f (_ "address@hidden: binding not found")
+ (package-name package)
+ (package-version package)))))))
+ ((mod . modules)
+ (let ((next (lambda () (search modules))))
+ (local-search (module-name mod) mod next))))))
+ (define (local-search module-name iface k)
+ (let lp ((bindings (module-map cons iface)))
+ (match bindings
+ (() (k))
+ (((sym . var) . bindings)
+ (if (eq? (variable-ref var) package)
+ (values module-name sym)
+ (lp bindings))))))
+ (cond
+ ((package-location package)
+ => (lambda (loc)
+ (cond
+ ((file-name->module-name (location-file loc))
+ => (lambda (module-name)
+ (cond
+ ((false-if-exception (resolve-interface module-name))
+ => (lambda (iface)
+ (let ((def (string->symbol (package-name package))))
+ (cond
+ ((and (module-variable iface def)
+ (eq? (module-ref iface def) package))
+ (values module-name def))
+ (else
+ (local-search module-name iface global-search))))))
+ (else (global-search)))))
+ (else (global-search)))))
+ (else (global-search))))