byKey and byValue: properties or methods?

[Peter Alexander]

On 18/01/12 12:52 AM, Timon Gehr wrote:
> On 01/18/2012 01:40 AM, Jonathan M Davis wrote:
>> On Tuesday, January 17, 2012 19:31:25 bearophile wrote:
>>> Nick Sabalausky:
>>>> Without properties, member function access *ANY* many value
>>>> accesses are "a.b()". Is this member value a plain-old-var or a
>>>> function?
>>>> Who knows! It's a leeked out implementation detail, hooray!
>>>
>>> I have a partially related question.
>>>
>>> Currently this code compiles even with -property:
>>>
>>> void main() {
>>> int[int] aa = [1:2];
>>> auto byval = aa.byValue();
>>> }
>>>
>>> But I think byValue is a property, so isn't it right to give a
>>> compilation
>>> error if you add () after the name of a property?
>>
>> Definitely a bug. Strict enforcement requires that parens be used on all
>> function calls and that no properties use parens. If you use parens on
>> them,
>> that would mean that you're using them on the return value of the
>> property
>> (e.g. opCall) - and in fact, that's one of the main reasons that
>> @property was
>> added in the first place, since without enforcement, property
>> functions which
>> return a delegate result in an ambiguity.
>>
>> - Jonathan M Davis
>
> A related and way more embarrassing problem is that lazy function
> parameters have the same issue.
>
> This program prints nothing:
> import std.stdio;
> void foo(lazy void delegate() dg){
> dg();
> }
> void main(){
> foo({writeln("hello");});
> }

Perhaps I'm wrong, but this issue is different.

The code you have written is something that would be written by someone 
that doesn't understand how lazy works. You have to use () to un-lazy 
it, and then () again to invoke the delegate. There is no ambiguity like 
there is with property delegates.