property syntax strawman

[Johan Granberg]

Walter Bright wrote:

> Having optional parentheses does lead to unresolvable ambiguities. How
> much of a problem that really is is debatable, but let's assume it
> should be resolved. To resolve it, a property must be distinguishable
> from a regular function.
> 
> One way is to simply add a "property" attribute keyword:
> 
>    property bool empty() { ... }
>    property void empty(bool b) { ... }
> 
> The problem is that:
> 
> 1. there are a lot of keywords already
> 2. keywords are global things
> 
> The alternative is to have a unique syntax for properties. Ideally, the
> syntax should be intuitive and mimic its use. After much fiddling, and
> based on n.g. suggestions, Andrei and I penciled in:
> 
>    bool empty { ... }
>    void empty=(bool b) { ... }
> 
> The only problem is when a declaration but not definition is desired:
> 
>    bool empty;
> 
> but oops! That defines a field. So we came up with essentially a hack:
> 
>    bool empty{}
> 
> i.e. the {} means the getter is declared, but defined elsewhere.
> 
> What do you think?

It solvs the ambiguities so it would work, might be nicer syntaxes out their
but it solvs the main problem.