On Sunday, 12 September 2021 at 01:48:07 UTC, H. S. Teoh wrote:
> On Sun, Sep 12, 2021 at 01:08:17AM +0000, Alex Bryan via Digitalmars-d-learn wrote:
> I am having trouble discovering what the proper (or at least a proper) way is to write a function that can take either a static or dynamic array as a parameter. My current implementation consists of 2 overloaded functions (one takes a dynamic array, the other takes a static array) with 99% copy/pasted code. My intuition tells me this is dirty, and there's a better way to do this with templates, but for the life of me I just can't figure it out. Would someone be so kind as to please help me out?
[...]
Just make the function take an array parameter. Static arrays will decay into a slice (though my recommendation is to explicitly slice it with the [] operator):
auto myFunction(T[] data) { ... }
T[10] staticArr;
T[] dynArr = [ ... ];
myFunction(staticArr); // implicit slice, not recommended
myFunction(staticArr[]); // explicit slice, better
myFunction(dynArr);
T
So it turns out my issue was that my function had an unnecessary ref:
auto myFunction(ref T[] data) { ... }
T[10] staticArr;
T[] dynArr = [ ... ];
myFunction(staticArr); // does not compile
myFunction(staticArr[]); // does not compile
myFunction(dynArr); // compiles
Since I was modifying the contents of data, I thought I needed the ref, but this is not the case. Removing the ref and the code works as you described.
Let me see if I can summarize what I've learned (and ask additional questions):
T[] data is essentially already a reference since it contains a pointer and a length and allows you to modify the contents it points to, but if I wanted to modify either the pointer or length in T[] data in that function (for some reason) I'd need to pass it in as a ref?
T[] dynArr can be passed (by reference) to a function that takes ref T[] data but T[10] data cannot? Why not?
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