The "no gc" crowd

[Walter Bright]

On 10/10/2013 12:51 AM, Jacob Carlborg wrote:
> On 2013-10-10 09:18, Walter Bright wrote:
>
>> 1. Shared data cannot be passed to regular functions.
>
> That I understand.
>
>> 2. Functions that create data structures would have to know in advance
>> that they'll be creating a shared object. I'm not so sure this would not
>> be an invasive change.
>
> If the function doesn't know it creates shared data it will assume it's not and
> it won't use any synchronization. Then suddenly someone casts it to "shared" and
> you're in trouble.

Same comment as for immutable data - create the data structure as thread local, 
because of (1), and then cast to shared and hand it to another thread.

>
>> 3. Immutable data is implicitly shared. But it is not created immutable
>> - it is created as mutable data, then set to some state, then cast to
>> immutable.
>
> It should be possible to create immutable data in the first place. No cast
> should be required.
>