Pádraig Brady wrote:
> > If a string starts with a sequence that requires $'' quoting followed
> > by a \' and then another charactrer requiring $'' quoting, the '$' at
> > the start of the quoted string ends up missing:
> >
> > $ env printf '%q\n' $'\1\'\2'
> > '\001'\'''$'\002'
>
> Indeed that is a bug.
> I'll be able to have a look at this tomorrow.
The '$' at the beginning is only missing in specific cases:
$ ./printf '%q\n' $'\1\'\2'
'\001'\'''$'\002'
$ ./printf '%q\n' $'a\1\'\2'
'''a'$'\001'\'''$'\002'
$ ./printf '%q\n' $'\1\'\2x'
''$'\001'\'''$'\002''x'
Also, let me apply some documentation improvement to the .h file (attached).
Bruno
>From 4d694d878f8792d510f5d30eaaf9d51c7b48ca10 Mon Sep 17 00:00:00 2001
From: Bruno Haible <br...@clisp.org>
Date: Sun, 31 Mar 2024 22:56:14 +0200
Subject: [PATCH] quotearg: Improve documentation.
* lib/quotearg.h: Refer to specification of $'...' syntax. Document a
limitation of QA_ELIDE_OUTER_QUOTES.
---
ChangeLog | 6 ++++++
lib/quotearg.h | 12 +++++++++---
2 files changed, 15 insertions(+), 3 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index ffae5513ae..182a894039 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2024-03-31 Bruno Haible <br...@clisp.org>
+
+ quotearg: Improve documentation.
+ * lib/quotearg.h: Refer to specification of $'...' syntax. Document a
+ limitation of QA_ELIDE_OUTER_QUOTES.
+
2024-03-31 Bruno Haible <br...@clisp.org>
canonicalize[-lgpl] tests: Fix test failure on musl libc.
diff --git a/lib/quotearg.h b/lib/quotearg.h
index 4e9099fff4..202b79f33e 100644
--- a/lib/quotearg.h
+++ b/lib/quotearg.h
@@ -80,7 +80,8 @@ enum quoting_style
/* Quote names for the shell if they contain shell metacharacters
or other problematic characters (ls --quoting-style=shell-escape).
- Non printable characters are quoted using the $'...' syntax,
+ Non printable characters are quoted using the $'...' syntax
+ <https://www.gnu.org/software/bash/manual/html_node/ANSI_002dC-Quoting.html>,
which originated in ksh93 and is widely supported by most shells,
and proposed for inclusion in POSIX.
@@ -95,7 +96,8 @@ enum quoting_style
/* Quote names for the shell even if they would normally not
require quoting (ls --quoting-style=shell-escape).
- Non printable characters are quoted using the $'...' syntax,
+ Non printable characters are quoted using the $'...' syntax
+ <https://www.gnu.org/software/bash/manual/html_node/ANSI_002dC-Quoting.html>,
which originated in ksh93 and is widely supported by most shells,
and proposed for inclusion in POSIX. Behaves like
shell_escape_quoting_style if QA_ELIDE_OUTER_QUOTES is in effect.
@@ -253,7 +255,11 @@ enum quoting_flags
/* Omit the surrounding quote characters if no escaped characters
are encountered. Note that if no other character needs
- escaping, then neither does the escape character. */
+ escaping, then neither does the escape character.
+ *Attention!* This flag is unsupported in combination with the styles
+ shell_escape_quoting_style and shell_escape_always_quoting_style
+ (because in this situation it cannot handle strings that start
+ with a non-printable character). */
QA_ELIDE_OUTER_QUOTES = 0x02,
/* In the c_quoting_style and c_maybe_quoting_style, split ANSI
--
2.34.1
