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.
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.
regards, tom lane