allocate hash table manually

[Jari-Matti Mäkelä]

Mildred wrote:
> Le mar 05/09/2006 __ 20:01 Johan Granberg __ __crit:
>> I think this is what I have used.
>>
>> class Value {
>> 	...
>> 	protected Value[char[]] _environment = null;
>> 	...
>> 	public void env_make(Stack S){
>> 		Value[char[]] e;
>> 		_environment = e;
>> 	}
>> 	...
>> }
> 
> Thanks, that helps me.
> 
> Isn't there a solution with the new keyword, it is the normal way to
> allocate on the heap, no ?

An empty hash is already "null" by default. Basically you're doing
something stupid here - see this example:

template Hash(K,V) {
        V[K] Hash() {
                V[K] tmp;
                return tmp;
        }
}

void main() {
        int[int] a;
        assert(a is null);
        a[1] = 1;
        assert(a !is null);
        a = Hash!(int, int);
        assert(a is null);
        a[1] = 1;
        assert(a !is null);
        a = Hash!(int, int);
        assert(a is null);
}

The compiler indicates a hash is empty by returning a null. Here Hash!
creates an empty hash and returns it - hash array literals can be
implemented in the same fashion.