`shelx` should support dollar-single-quotes quoting

[calestyo]

Feature or enhancement

Hey.

POSIX.1-2024 added dollar-single-quotes quoting to the Shell Command Language like e.g. $'a\nb' for

'a
b'

(using single-quotes quoting).

It would be nice if shlex and in particular shlex.quote would support this, especially as it allows to keep quoted strings in a single line and avoid other special characters (like HT) which might get lost in some circumstances (e.g. when copy and pasting such strings).

If implemented, the use of dollar-single-quotes quoting should probably be optional, defaulting to no use it. Especially as there are still POSIX "compliant" shells which do not support it yet.

Cheers,
Chris.

Has this already been discussed elsewhere?

This is a minor feature, which does not need previous discussion elsewhere

Links to previous discussion of this feature:

No response

[utam-1]

@calestyo, can I work on this issue? I am thinking we could introduce a new parsing API for quote like : shlex.quote(s, *, force=False, dollar_quotation=False) (s would be the string we'd process), It'll be off by default, because of the fact older shells interpret $ differently. Of course there'll be certain cases that we'd need to deal with when implementing this and extending it to shlex.split().

[calestyo]

Sure. :-)

I'd probably use dollar_single_quote= though... but maybe just personal taste.

I think it might make sense to document the values like so:
False / True don't / do use dollar single quotes - i.e. not truth values

This would leave the API extensible should there ever be the wish to make it even more configurable, so that one could e.g. also set

• single_quote=
• double_quote=
• double_quote=
• backslash_escape=
  to specify which shall be used and which not, with True just telling that they might be used.

By recognising non-boolean true/false truth value now, this could even be extended so that the above options take numbers which would allow to give a precedence of the quoting style.

I mean it's unlikely that this would ever be needed... but if so, the API would the facilitate it.

Cheers,
Chris.

[utam-1]

Sure. :-)

I'd probably use dollar_single_quote= though... but maybe just personal taste.

I think it might make sense to document the values like so: False / True don't / do use dollar single quotes - i.e. not truth values

This would leave the API extensible should there ever be the wish to make it even more configurable, so that one could e.g. also set

• single_quote=
• double_quote=
• double_quote=
• backslash_escape=
  to specify which shall be used and which not, with True just telling that they might be used.

By recognising non-boolean true/false truth value now, this could even be extended so that the above options take numbers which would allow to give a precedence of the quoting style.

I mean it's unlikely that this would ever be needed... but if so, the API would the facilitate it.

Cheers, Chris.

dollar_single_quote sounds good too, and the extensibility of the API you suggested also seems plausible. However, I think before we go ahead with the implementation, we'd need an approval of sort from the maintainers if something like this is desired or not.

[picnixz]

I am against. This should come with a 3rd party library. And please open DPO threads for that instead of issues first. As you noted some shells do not support this.