Re: dollar quoting

Tom Lane wrote:

>Andrew Dunstan <andrew@dunslane.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?
>>    
>>
>
>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.

>
>There was some discussion awhile back of converting psql to use flex
>for interpreting its input, but I dunno how practical that really is.
>I don't know how you get flex to do reasonable stuff with an incomplete
>input string.  Still, it might be worth looking into.
>
>  
>

That's what made me not even think about it. If someone better versed in 
this stuff than me wants to do it then more power to them.

cheers

andrew