From 6561c943fa134ca1e2a17e43f8f5498fca9b1560 Mon Sep 17 00:00:00 2001
From: Maxime Devos <maximedevos@telenet.be>
Date: Sun, 18 Apr 2021 13:15:08 +0200
Subject: [PATCH 2/2] =?UTF-8?q?doc:=20Document=20new=20functionality=20of?=
 =?UTF-8?q?=20=E2=80=98which=E2=80=99.?=
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* doc/guix.texi (File Search)[which]: Document the optional
  'inputs' argument, and give an example on how to use the
  procedure.
---
 doc/guix.texi | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/doc/guix.texi b/doc/guix.texi
index 6464fa32cb..365cb13604 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -87,6 +87,7 @@ Copyright @copyright{} 2020 Daniel Brooks@*
 Copyright @copyright{} 2020 John Soo@*
 Copyright @copyright{} 2020 Jonathan Brielmaier@*
 Copyright @copyright{} 2020 Edgar Vincent@*
+Copyright @copyright{} 2021 Maxime Devos@*
 
 Permission is granted to copy, distribute and/or modify this document
 under the terms of the GNU Free Documentation License, Version 1.3 or
@@ -8598,11 +8599,25 @@ the root of the Guix source tree:
 @result{} ("./libformat.a" "./libstore.a" @dots{})
 @end lisp
 
-@deffn {Scheme Procedure} which @var{program}
+@deffn {Scheme Procedure} which @var{program} [@var{inputs}=#false]
 Return the complete file name for @var{program} as found in
-@code{$PATH}, or @code{#f} if @var{program} could not be found.
+@code{$PATH}, or @code{#false} if @var{program} could not be found.
+If @var{INPUTS} is not @code{#false}, instead look in the
+@file{/bin} and @file{/sbin} subdirectories of @var{INPUTS}.
+@var{inputs} is an alist; its keys are ignored."
 @end deffn
 
+Here is an example using the @code{which} procedure in a build phase:
+
+@lisp
+(lambda* (#:key outputs inputs #:allow-other-keys)
+  (let ((growpart (string-append (assoc-ref outputs "out")
+                                          "/bin/growpart")))
+     (wrap-program growpart
+                   `("PATH" ":" prefix (,(dirname (which "sfdisk" inputs))
+                                        ,(dirname (which "readlink" inputs)))))))
+@end lisp
+
 @subsection Build Phases
 
 @cindex build phases
-- 
2.31.1