Re: expression parser change

[Pavel Holejsovsky <pavel.holejsovsky@...>]

On 12/17/2010 1:51 PM, Roberto Ierusalimschy wrote:
> > The point is to get rid of prefixexp folding it into simpleexp.
> > The prefixexp rule just limits the syntax without any reason.
> >
> > [...]
> >
> > Of course, it's 100% backwards compatible.
>
> It is not...
>
> The following chunk has the same meaning in 5.1 and 5.2 alpha,
> but gets a different meaning with this change:
>
>    a = nil
>    (print or io.write)(a)

So how about more constrained version I suggested before, i.e. leave 
prefixexp in but extend it so that it can contain also literal constant?

 - prefixexp ::= var | functioncall | ‘(’ exp ‘)’
+ prefixexp ::= var | functioncall | ‘(’ exp ‘)’ | String

Pavel