[latex3-commits] [git/LaTeX3-latex3-latex3] gh590: Improve documentation of \ur escape (see #590) [ci skip] (6000db824)

[Bruno Le Floch]

Repository : https://github.com/latex3/latex3
On branch  : gh590
Link       : https://github.com/latex3/latex3/commit/6000db824f175136f06fbd078dda8fdc29d341c7

>---------------------------------------------------------------

commit 6000db824f175136f06fbd078dda8fdc29d341c7
Author: Bruno Le Floch <blflatex at gmail.com>
Date:   Mon Apr 26 15:58:30 2021 +0200

    Improve documentation of \ur escape (see #590) [ci skip]


>---------------------------------------------------------------

6000db824f175136f06fbd078dda8fdc29d341c7
 l3kernel/l3regex.dtx | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/l3kernel/l3regex.dtx b/l3kernel/l3regex.dtx
index 5d3f5936d..40dfb15f8 100644
--- a/l3kernel/l3regex.dtx
+++ b/l3kernel/l3regex.dtx
@@ -339,9 +339,13 @@
 %
 % The |\ur| escape sequence allows to insert the contents of a |regex|
 % variable into a larger regular expression.  For instance,
-% |A\ur{l_tmpa_regex}B| matches the tokens |A| and |B| separated by
+% |A\ur{l_tmpa_regex}D| matches the tokens |A| and |D| separated by
 % something that matches the regular expression
-% \cs[no-index]{l_tmpa_regex}.
+% \cs[no-index]{l_tmpa_regex}.  This behaves as if a (non-capturing)
+% group were surrounding \cs[no-index]{l_tmpa_regex}: for instance, if
+% that regex variable has value \verb"B|C", then |A\ur{l_tmpa_regex}D|
+% is equivalent to \verb"A(?:B|C)D" (matching |ABD| or |ACD|) and not to
+% \verb"AB|CD" (matching |AB| or |CD|).
 %
 % The option |(?i)| makes the match case insensitive (identifying
 % \texttt{A}--\texttt{Z} with \texttt{a}--\texttt{z}; no Unicode support