Re: [RFC] [VOTE] Constant scalar expressions

Hi all, On Thu, Nov 21, 2013 at 6:11 AM, Bob Weinand <bobwei9@hotmail.com> wrote: > That'd just be outside of this RFC's scope: > > const ABC = [1, 2]; > > is currently not allowed. Also you can't write ABC[0]. That'd be a whole > other RFC to add array support for constants. > I understand it requires new codes(and flag) to make a constant array/object. > So we could enable it for (static) properties, but why should we? > > Additions of arrays would be the only valid operation, but can you imagine > _any_ use case where we'd need that when the only dynamic operands ( > constants) can't be arrays? > I just thought constant array/object is useful for application settings, etc that should not be changed. Anyway, constant variables are useful for VM/op code optimization. include('foo.php'); // const a = 123; const b = a; is allowed currently. We may restrict this behavior only to the same file, so that VM/op code optimization can be done. Currently, no expression is allowed with 'const'. Defining 'const' using another constant with the same value is useless. It's a bad coding practice in many case, I suppose. I understand use cases of scalar expressions with constants, but I'm concerned loosing door for further optimizations. (e.g. $x = $x + 123 is faster than $x = $x + a, where a is 123 in constant var hash) We may be better to restrict expressions with constants only to the same file even if we loose some benefits/flexibility in user code. Is this discussed? Regards, -- Yasuo Ohgaki yohgaki@ohgaki.net