Re: [PATCH] Add shell-quasiquote.

[Paul Eggert]

Taylan Ulrich Bayırlı/Kammer wrote:
> > I must have missed it then, because all I remember are the cases (1)
> > >of running /bin/if (which is trivial and is not a realistic example),
> > >and (2) of installations with nonstandard shells (a problem that
> > >shqq--quote-string does not fix). It has been a long thread; quite
> > >possibly I missed something.
> Yeah, you missed the part about risk of code injection.:-)

Code injection occurs because of (2), right? So it's not a risk that 
shqq--quote-string would put much of a dent in.

I thought the complaint was about shell-quote-argument's implementation. But if 
it's merely about its documentation, then perhaps we can reword it to address 
your concerns. I briefly looked at your most recent docstring proposal in 
Bug#21702 and I'm afraid it is is pretty wordy and is not technically correct. 
For example, (shell-quote-argument "\0") does not produce a string that will be 
parsed as one token whose value will be exactly that of shell-quote-argument's 
argument in any POSIX-conforming shell. This is because you can't put NUL 
characters into a command argument in POSIX.

It'd be better to have docstring wording that is shorter and conveys the gist of 
what shell-quote-argument is for, without going into a lot of technical detail 
that will bog down the reader and may well be wrong anyway. Details about what 
is "safe" and what "safe" means can go into the manual.