Re: A bug in scan.l

Gokulakannan Somasundaram <gokul007(at)gmail(dot)com> writes:
> Well, i am at a very beginner level with Flex. I could see how flex works
> with it even if it is a ambiguity. Since it matches the rule with the
> maximum text and we don't allow a new line character in the rule, it works
> fine. Even in LL(1), it works fine, but throws warnings. So i just thought
> of suggesting to remove the ambiguity.

Well, that whole rule is only there for implementation-specific reasons
--- a flex scanner is faster if it doesn't need to back up. You might
be best off to just remove the anti-backup rules in the LL translation.

> But do we need to allow comments as part of unicode escapes?

If they're like normal strings, yes.

regression=# select 'this is' -- comment
regression-# ' one string';
?column?
--------------------
this is one string
(1 row)

Don't blame us, blame the SQL committee. This was not one of their
better ideas IMO.

regards, tom lane