Re: proposal: unescape_text function

st 2. 12. 2020 v 9:23 odesílatel Peter Eisentraut <
peter(dot)eisentraut(at)enterprisedb(dot)com> napsal:

> On 2020-11-30 22:15, Pavel Stehule wrote:
> > I would like some supporting documentation on this. So far we only
> > have
> > one stackoverflow question, and then this implementation, and they
> are
> > not even the same format. My worry is that if there is not precise
> > specification, then people are going to want to add things in the
> > future, and there will be no way to analyze such requests in a
> > principled way.
> >
> >
> > I checked this and it is "prefix backslash-u hex" used by Java,
> > JavaScript or RTF -
> > https://billposer.org/Software/ListOfRepresentations.html
>
> Heh. The fact that there is a table of two dozen possible
> representations kind of proves my point that we should be deliberate in
> picking one.
>
> I do see Oracle unistr() on that list, which appears to be very similar
> to what you are trying to do here. Maybe look into aligning with that.
>

unistr is a primitive form of proposed function. But it can be used as a
base. The format is compatible with our "4.1.2.3. String Constants with
Unicode Escapes".

What do you think about the following proposal?

1. unistr(text) .. compatible with Postgres unicode escapes - it is
enhanced against Oracle, because Oracle's unistr doesn't support 6 digits
unicodes.

2. there can be optional parameter "prefix" with default "\". But with "\u"
it can be compatible with Java or Python.

What do you think about it?

Pavel