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[bug#53909] [PATCH 2/4] ui: 'with-paginated-output-port' gives access to
From: |
Ludovic Courtès |
Subject: |
[bug#53909] [PATCH 2/4] ui: 'with-paginated-output-port' gives access to the wrapped port. |
Date: |
Wed, 9 Feb 2022 23:17:10 +0100 |
* guix/ui.scm (pager-port-mapping): New variable.
(pager-wrapped-port): New procedure.
(call-with-paginated-output-port): Parameterize 'pager-port-mapping'.
---
guix/ui.scm | 20 +++++++++++++++++++-
1 file changed, 19 insertions(+), 1 deletion(-)
diff --git a/guix/ui.scm b/guix/ui.scm
index 093de1b4ab..d1f92ce7be 100644
--- a/guix/ui.scm
+++ b/guix/ui.scm
@@ -124,6 +124,7 @@ (define-module (guix ui)
file-hyperlink
location->hyperlink
+ pager-wrapped-port
with-paginated-output-port
relevance
package-relevance
@@ -1665,6 +1666,20 @@ (define (package-relevance package regexps)
zero means that PACKAGE does not match any of REGEXPS."
(relevance package regexps %package-metrics))
+(define pager-port-mapping
+ ;; If a pager is being used, via 'with-paginated-output-port', this maps the
+ ;; pager port (pipe) to the underlying output port.
+ (make-parameter #f))
+
+(define* (pager-wrapped-port #:optional (port (current-output-port)))
+ "If PORT is a pipe to a pager created by 'with-paginated-output-port',
+return the underlying port. Otherwise return #f."
+ (match (pager-port-mapping)
+ ((pager . wrapped)
+ (and (eq? pager port) wrapped))
+ (_
+ #f)))
+
(define* (call-with-paginated-output-port proc
#:key (less-options "FrX"))
(let ((pager-command-line (or (getenv "GUIX_PAGER")
@@ -1691,7 +1706,10 @@ (define* (call-with-paginated-output-port proc
char-set:whitespace))))))
(dynamic-wind
(const #t)
- (lambda () (proc pager))
+ (lambda ()
+ (parameterize ((pager-port-mapping
+ (cons pager (current-output-port))))
+ (proc pager)))
(lambda () (close-pipe pager))))
(proc (current-output-port)))))
--
2.34.0