PhobosWatch: manifest => enum

["Jérôme M. Berger"]

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Walter Bright wrote:
> Jérôme M. Berger wrote:
>> Walter Bright wrote:
>
>> the only question is what syntax to use: either
>> a counter-intuitive extension to enums or a new keyword (or a minor
>> extension to the alias keyword as was suggested by somebody).
> 
> I found the "use an alias when declaring one constant" and "use an enum
> when declaring more than one constant" to be difficult to justify. It's
> like saying arrays with only one element should not be allowed.
> 
	I don't think anybody suggested using an enum for declaring more
than one constant. The suggestions were more on the line of:

keyword {
   int   x = 42;
   float y = 42.42;
}

	Where "keyword" could be one of "constant", "invariant", "alias" or
anything that means constant (but not "enum", anymore than
"abstract" or "cat": those mean something else).

> 
>>     BTW, I think it was Janice who suggested that the compiler should
>> know whether a constant needs to be manifest or not (depending on
>> whether its address is taken somewhere). This would remove the need
>> for a way to distinguish manifest constants explicitly. Any thoughts
>> on that?
> 
> The reason this won't work is because:
>     const int x = 3;
> will type x as const(int), not int. There needs to be a way to declare a
> constant of type int.

	Er, why? Taking "&x" should return a "const (int)*" and using "x"
directly should always work so long as you don't modify it. Are you
telling us that the following code will fail:

void func (int param)
{
}

const int x = 42;
int y = x;              // <= This should work
func (x);               // <= This should work too

	Or is there something I'm missing here?

		Jerome
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