On 03/10/2015 08:00 AM, John Colvin wrote:
> On Tuesday, 10 March 2015 at 14:41:00 UTC, Logan Capaldo wrote:
>> On Monday, 9 March 2015 at 22:15:43 UTC, Ali Çehreli wrote:
>>> You are right. I had the same observation at minute 11:27 below,
>>> where I warn against UFCS with assumeWontThrow:
>>>
>>>
>>>
http://www.youtube.com/watch?feature=player_detailpage&v=oF8K4-bieaw#t=687
>>>
>>>
>>> Ali
>>
>> Sorry, which is right?
You are right that it is confusing. :)
>> I know ifThrown is lazy, I'm curious about the
>> "amount" of the expression that is evaluated lazily.
>>
>>
>> a.b().c().assumeWontThrow vs. a.b().c().assumeWontThrow
>> ^--+----^ ^-^
>> | |
>> +- lazy? +- lazy?
As John Colvin said, the first one is right. A test:
import std.stdio;
struct S
{}
S a(S s)
{
writeln("entered a");
return s;
}
S b(S s)
{
writeln("entered b");
return s;
}
void lazily(T)(lazy T expression)
{
writeln("entered lazily");
expression();
}
void main()
{
S().a.b.lazily;
}
Outputs
entered lazily
entered a
entered b
>> The video seems to say "don't use lazy functions with UFCS because you
>> might think the lazy part gets evaluated first, when it does not".
>> Seems reasonable, although I don't know it's any different than
>> assumeWontThrow(f()).
You are right again. :) However, putting the lazy-taking function
"outside" the whole expression makes it visible right away, making easy
for me to realize that the execution order may be different from common
chains.
Ali
