On Sun, 24 Apr 2011 07:33:30 -0400, Jacob Carlborg <[email protected]> wrote:
On 23 apr 2011, at 23:20, Robert Jacques wrote:
On Sat, 23 Apr 2011 16:06:35 -0400, Jacob Carlborg <[email protected]> wrote:
On 23 apr 2011, at 17:32, David Simcha wrote:
On 4/23/2011 11:24 AM, Jacob Carlborg wrote:
I think I would like to have something in the middle of strict and
loose semantics. I would like that functions marked with @property
have to be called like a field:
auto bar = foo.field;
foo.field = 3;
But functions not marked with @property still can be called without
the parentheses:
foo.bar();
foo.bar;
Maybe there's been some misunderstanding, but actually this is what
loose semantics means. Loose semantics (at least as I understand
them) mean stuff marked @property would not be callable using method
syntax, and this rule would be used to disambiguate the corner cases,
but nothing would change for stuff not marked @property.
Ok, then I probably misunderstood. What about:
writeln = "foo";
is that already fixed?
If by fixed, you mean doesn't compile, then yes, it's fixed. But this
might be a quality of implementation issue, regarding method syntax and
templates and not a true theoretical fix. Case in point: printf = "foo"
works. However, while ugly, neither writeln = "foo" nor printf = "foo"
are doing something the original author didn't intend. The greater
violators (which actually caused bug reports/confusion) are those where
the statements became nonsense, like math_function = 5 or
obj.factory_method = 6.[1] Fixes for most of these issues exist: Not
using the result from a strongly pure function should be an error, not
matter how it's called. And const/immutable methods shouldn't be
assignable, since you can't assign to a const or immutable variable.
Static/free functions can't be marked const/immutable, but considering
the only thing they can modify is global state, pure is equivalent. So
neither strongly nor weakly pure functions should be assignable.
If writeln = "foo"; doesn't compile but printf = "foo"; does then I
would consider it not fixed. The way I would want @property to behave is
disallow bar = "foo"; for functions not marked with @property. But still
allow functions not marked with @property to be callable without
parentheses.
I have not heard this particular combination before; thank you. More
choices are always appreciated. There are real, practical use cases for
not-@property methods with write-only field semantics, which this would
prevent. And between a real use case and a synthetic straw-man, I believe
the use case should win. However, I am interested in any of the practical
issues which inspired writeln = "foo", if you know of any.
Also, this and another post have given me an idea: what if non-@property
methods could be assigned to if and only if a valid 'getter' also existed.
This would still 'fix' writeln = "foo" but be a less restrictive than an
outright ban.
_______________________________________________
phobos mailing list
[email protected]
http://lists.puremagic.com/mailman/listinfo/phobos
