• Michiel (10/10) Feb 21 2007 I'm now implementing the toHash() function of my new Set class. But I'm
• Michiel (11/19) Feb 21 2007 I think I found a way in Phobos, but it might not be the most elegant
• Jarrett Billingsley (13/19) Feb 21 2007 You can use the .getHash method of the typeinfo any type, and it'll use ...
• Michiel (6/26) Feb 22 2007 That also works nicely! I tried something similar, just not exactly like

Michiel <nomail please.com> writes:

I'm now implementing the toHash() function of my new Set class. But I'm
not sure how to extract hash-information from an associative array of
which the key-type can be anything. The values are irrelevant. So you
might see the problem as extracting hash-information from its .keys array.

I'm sure the hash-information of its key-type can be retrieved, since
that's how the associative array works in the first place. How do I
retrieve it manually?

Thanks!

-- 
Michiel

Michiel <nomail please.com> writes:

Michiel wrote:

 I'm now implementing the toHash() function of my new Set class. But I'm
 not sure how to extract hash-information from an associative array of
 which the key-type can be anything. The values are irrelevant. So you
 might see the problem as extracting hash-information from its .keys array.
 
 I'm sure the hash-information of its key-type can be retrieved, since
 that's how the associative array works in the first place. How do I
 retrieve it manually?

I think I found a way in Phobos, but it might not be the most elegant
one. I used std.boxer to pack each element of the array into a box. Then
I call the Box.toHash() function on each and use the sum to calculate
the sets hash.

Is there a better way?

It does seem to work. I can now have sets of sets of sets of whatever,
and it still works as expected.

I'll continue to tweak the class a bit and then I'll publish it here.

-- 
Michiel

"Jarrett Billingsley" <kb3ctd2 yahoo.com> writes:

"Michiel" <nomail please.com> wrote in message 
news:eritp3$d3j$1 digitalmars.com...
 Michiel wrote:

 I think I found a way in Phobos, but it might not be the most elegant
 one. I used std.boxer to pack each element of the array into a box. Then
 I call the Box.toHash() function on each and use the sum to calculate
 the sets hash.

 Is there a better way?

You can use the .getHash method of the typeinfo any type, and it'll use the 
built in hashing function.

class Set(T)
{
    ...
    T[] values; // or however you store them

    void someFunc(T data)
    {
        hash_t hash = typeid(T).getHash(&data);
    }
} 

Michiel <nomail please.com> writes:

Jarrett Billingsley wrote:

 I think I found a way in Phobos, but it might not be the most elegant
 one. I used std.boxer to pack each element of the array into a box. Then
 I call the Box.toHash() function on each and use the sum to calculate
 the sets hash.

 Is there a better way?

 
 You can use the .getHash method of the typeinfo any type, and it'll use the 
 built in hashing function.
 
 class Set(T)
 {
     ...
     T[] values; // or however you store them
 
     void someFunc(T data)
     {
         hash_t hash = typeid(T).getHash(&data);
     }
 } 

That also works nicely! I tried something similar, just not exactly like
that. Anyway, it's more elegant than my box way.

Thanks!

-- 
Michiel