Hi Pavel,
> > [...]
> > This patch fixes both issues, and makes the IFS handling a bit more robust.
> > [...]
>
> > - case $_fpf_arg in
> > + case "$_fpf_arg" in
> > [...]
> > - fpf_dirs=$1 ; shift
> > - fpf_cb=$1 ; shift
> > + fpf_dirs="$1"; shift
> > + fpf_cb="$1"; shift
> > [...]
>
> ... and so on, I don't think it is more robust. At least according to
> Autoconf's Shellology [1] it should be actually better to write it the
> other way around (without additional quotes).
I do think it is more robust, because
* The number one mistake in shell scripts (measured by frequency of
occurrence) is to reference variables without double quotes when word
splitting is in fact undesired.
* Simple rules are easier to follow by programmers, resulting in fewer bugs.
* The rule
"Always double-quote shell variable references, except if you DO
want word-splitting."
is simpler than
"Always double-quote shell variable references, except if you DO
want word-splitting OR in the right-hand side of assignments OR
as argument of 'case' statements."
The text that you quote says two different things:
* Backquotes inside double-quotes are hairy.
There is a simple rule to avoid them: When you have a backquote
expression, always first assign its result to a variable. Then use
the variable (with double-quotes, usually).
* Bash 4.1 has a bug when you WANT word splitting.
These two things don't make my style rule
"Always double-quote shell variable references, except if you DO
want word-splitting."
less robust.
> FTR, Gary Vaughan has wrote a syntax checker rules for protecting us from
> adding such statements into libtool codebase.
Opinions regarding coding style differ. Gary is entitled to his opinion, as
much as I am entitled to mine.
Bruno
> [1] https://www.gnu.org/software/autoconf/manual/autoconf-2.69/html_node/
> Shell-Substitutions.html
