%graph-backends))
\f
+;;;
+;;; Displaying a path.
+;;;
+
+(define (display-path node1 node2 type)
+ "Display the shortest path from NODE1 to NODE2, of TYPE."
+ (mlet %store-monad ((path (shortest-path node1 node2 type)))
+ (define node-label
+ (let ((label (node-type-label type)))
+ ;; Special-case derivations and store items to print them in full,
+ ;; contrary to what their 'node-type-label' normally does.
+ (match-lambda
+ ((? derivation? drv) (derivation-file-name drv))
+ ((? string? str) str)
+ (node (label node)))))
+
+ (if path
+ (format #t "~{~a~%~}" (map node-label path))
+ (leave (G_ "no path from '~a' to '~a'~%")
+ (node-label node1) (node-label node2)))
+ (return #t)))
+
+\f
;;;
;;; Command-line options.
;;;
(lambda (opt name arg result)
(alist-cons 'node-type (lookup-node-type arg)
result)))
+ (option '("path") #f #f
+ (lambda (opt name arg result)
+ (alist-cons 'path? #t result)))
(option '("list-types") #f #f
(lambda (opt name arg result)
(list-node-types)
-t, --type=TYPE represent nodes of the given TYPE"))
(display (G_ "
--list-types list the available graph types"))
+ (display (G_ "
+ --path display the shortest path between the given nodes"))
(display (G_ "
-e, --expression=EXPR consider the package EXPR evaluates to"))
(display (G_ "
(mlet %store-monad ((_ (set-grafting #f))
(nodes (mapm %store-monad
(node-type-convert type)
- items)))
- (export-graph (concatenate nodes)
- (current-output-port)
- #:node-type type
- #:backend backend))
+ (reverse items))))
+ (if (assoc-ref opts 'path?)
+ (match nodes
+ (((node1 _ ...) (node2 _ ...))
+ (display-path node1 node2 type))
+ (_
+ (leave (G_ "'--path' option requires exactly two \
+nodes (given ~a)~%")
+ (length nodes))))
+ (export-graph (concatenate nodes)
+ (current-output-port)
+ #:node-type type
+ #:backend backend)))
#:system (assq-ref opts 'system)))))
#t)