Re: [HACKERS] dollar quoting

Andrew Dunstan wrote:

>
>
> Tom Lane wrote:
>
>> Andrew Dunstan <andrew(at)dunslane(dot)net> writes:
>>
>>
>>> After staring at the code for a long time, I think I see how to do
>>> this. It's complicated a bit by the fact that $ is a valid
>>> identifier character. So my current thinking is to say that if we
>>> see $ not in a quote and not preceded by a valid identifier char
>>> then it is the start of a $foo$ sequence. Or have I missed
>>> something? Can we validly see $ in any other context?
>>>
>>

I had missed one, though - numbered params in prepared statements. Fixed
in attached patch.

>>
>> Right, a $ should be considered to start a quote marker only if it's not
>> part of an identifier. The backend lexer doesn't have a problem with
>> this because it's written in flex, but I can imagine that getting it
>> right in psql's ad-hoc parser might be tricky.
>>
>
> I think it's doable, though. I seem to have a working patch, which I
> will send out for review soon.
>

Proof of Concept patch (i.e. not for application) attached for review.
The scanner changes are based on Tom's original, with some name/comment
changes and a more liberal pattern. The psql changes are all my own work
:-).

Comments welcome. Reviewers: I am not sure I got multi-byte stuff right
in psql/mainloop.c - please pay close attention to that.

If I'm not wildly off course I will polish this up and start on docs.

cheers

andrew