From: Brent Roman <brent@...>
Date: 2009-02-26T03:08:46+09:00
Subject: [ruby-core:22476] Re: YASNP (Yet Another Selector Namespace Proposal)


At least regarding blocks vs. a special keyword:

   There may be a middle way

If the parser were modified such that upon encountering the
EOF token, it terminated the current do/end block, then
:use could be a normal Kernel method that simply takes block,
without introducing spurious indentation.

use MyWorld do
....
<EOF>

This also allows quite handy expressions such as:

ruby -e "3.times do print 'Howdy, '"

or

eval "3.times do print 'Howdy, '"

There is still the question of whether EOF should terminate nested
do style blocks in order to handle:

use MyWorld do
use OtherWorld do
.....
<EOF>

This parser change certainly is easy to implement.
And, it cannot break any working code.

- brent


Charles Oliver Nutter-2 wrote:
> 
> Yukihiro Matsumoto wrote:
>> +1 to have some kind of selector namespace (it's planned for 2.0
>> anyway), but -1 for using block (or block-like syntax) to denote
>> namespace scope, because
>> 
>>   * it's not really a block
>>   * too small granularity for namespace switching might bring confusion
>> 
>> I'd prefer per file namespace switching.
> 
> I think it's impossible to have per-file without making "use" a special 
> keyword, ideally at the top of the file. The block syntax made more 
> sense to me because I knew exactly when it started and ended, and a 
> 'use' later in the file did not affect code that came before it. Also, 
> the example where I have both a namespace and a 'use' in the same file 
> would be impossible if the use applied to the whole file.
> 
> I'm willing to mock up anything else we want to try, including a 
> whole-file version.
> 
> - Charlie
> 
> 
> 

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