Do C++ performance optimisations apply to Julia?

[paulmelis]

@giordano

Note that assignment never modifies the memory object pointed to by a variable but rebinds the variable to something else. Your modx doesn’t really modify in-place anything. If for example you push! to x you’re actually modifying it and the caller would see it.

I think that was the point @skleinbo was trying to make about Julia’s pass-by-sharing. In contrast, in C++ you can use a reference variable to modify in-place (as the second example shows).