On Monday, 2 May 2016 at 08:46:31 UTC, Ali Çehreli wrote:
On 05/01/2016 12:54 PM, Xinok wrote:
> On Sunday, 1 May 2016 at 05:42:00 UTC, Ali Çehreli wrote:
>> On 04/30/2016 10:05 PM, Joel wrote:
>> > This has no effect:
>> > _bars.each!(a => { a._plots.fillColor = Color(255, 180, 0);
>> });
>>
>> This is a common issue especially for people who know
lambdas from
>> other languages. :)
>>
>> Your lambda does not do any work. Rather, your lambda
returns another
>> lambda, which is promptly ignored:
>
> Those are some discrete semantics. I know D pretty well and
even I
> didn't see the problem initially. Anybody else think it's
worth adding a
> warning to the compiler for this specific case?
A warning would be great but I don't see how it can cover all
cases. A special warning for std.algorithm.each might work but
this exact issue appeared on the main thread just a few minutes
ago:
http://forum.dlang.org/post/qsayoktyffczskrnm...@forum.dlang.org
alias funType = void function(int x);
funType fun = (x) => { assert(x); }; // cannot return
non-void from void function
Ali
Warning (better: disallowing altogether) about `=>` directly
followed by `{` should be enough to cover all cases. To express
that you really want a lambda returning a lambda, it can be
rewritten either as:
(x) => () { assert(x); }
or as:
(x) => ({ assert(x); })
This check can be done purely by looking at the tokens. Should we
someday introduce tuples with `{}`, the check needs to be done
after the node starting with `{` has been parsed to distinguish
between delegate and tuple literals.
