[squeak-dev] Re: Future examples (Re: Inbox: #future keyword for asynchronous message invocation)

Andreas Raab andreas.raab at gmx.de
Fri Dec 18 17:13:22 UTC 2009

Colin Putney wrote:
> On 2009-12-18, at 1:01 AM, Josh Gargus wrote:
>>> Pretty interesting. I'm a bit ambivalent about a magic compiler change like this, but you make a pretty strong case for it's usefulness.
>> That's why Andreas asked me to add the FutureMaker class and the Object future/future: implementations.  The same semantics are implemented without any compiler magic; the addition of FutureNode to the compiler is then merely an optimization.
> In that case I'd say let's hold off on the compiler changes, until we find that we're using #future so much that it should be inlined.  

Oops, sorry forgot to comment on this one. Although strictly speaking 
the inlining is optional, it is very, very desirable because one of the 
things the compiler does is omitting the need to generate return 
promises for every single future message being sent. Since the compiler 
knows whether the result of a message is being used or not, we can avoid 
creating promises for messages where the result isn't used. In practice, 
this turns out to be a significant improvement; for example in Teleplace 
the ratio is 4:1 for futures without result promises compared to those 
with (886:196 to be precise; this also gives you a feel for how much we 
use future messages - they are used more often than #collect: which has 
976 senders in the same image). I'd like to retain that optimization if 
at all possible.

   - Andreas

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