From 5ae3c5512e85189a47c859c6128adfd3bfc63159 Mon Sep 17 00:00:00 2001
From: Gabriel Wicki <gabriel@erlikon.ch>
Date: Thu, 13 Apr 2023 10:31:57 +0200
Subject: [PATCH] guix: build: utils: Clarify substitute* docstring with an
example.
* guix/build/utils.scm (substitute*): Add an example on how to match
end-of-line.
* doc/guix.texi (Build Utilities): Update the corresponding passage.
---
doc/guix.texi | 3 ++-
guix/build/utils.scm | 3 ++-
2 files changed, 4 insertions(+), 2 deletions(-)
@@ -10321,7 +10321,8 @@ Alternatively, @var{file} may be a list of file names, in which case
they are all subject to the substitutions.
Be careful about using @code{$} to match the end of a line; by itself it
-won't match the terminating newline of a line.
+won't match the terminating newline of a line, e.g. to match a whole
+line ending with a backslash, one needs a regex like @code{"(.*)\\\\\n$"}.
@end defmac
@subsection File Search
@@ -957,7 +957,8 @@ (define-syntax substitute*
all subject to the substitutions.
Be careful about using '$' to match the end of a line; by itself it won't
-match the terminating newline of a line."
+match the terminating newline of a line, e.g. to match a whole line ending
+with a backslash, one needs a regex like \"(.*)\\\\\n$\"."
((substitute* file ((regexp match-var ...) body ...) ...)
(let ()
(define (substitute-one-file file-name)
--
2.39.2