[julia-users] Simulating fixed-size arrays

[Carlos Becker]

Hello, I am trying to find out the best way to deal with immutables (or 
types) that contain fixed-size arrays, such as this:

# should have variable number of

# Uint64's

immutable Descriptor

   a1::Uint64 

   a2::Uint64 

   a3::Uint64 

   a4::Uint64

end

# should work with variable-size Descriptor

function myDist(x1::Descriptor,x2::Descriptor) :inline

        return count_ones(x1.a1 $ x2.a1) + count_ones(x1.a2 $ x2.a2) + 
count_ones(x1.a3 $ x2.a3) + count_ones(x1.a4 $ x2.a4)

end



In this specific case, Descriptor is 32-bytes wide, but I would like to 
make the code generic for different number of elements in the immutable.
If fixed-size arrays were available, this would be very easy, but which is 
a neat way of doing this with the current julia v0.3?

btw, the code above runs amazingly fast, using popcount instructions when 
available, almost c-speed ;)
This is good news for Julia indeed.

Thanks.