> Making a fun & interesting games is about rapid prototyping and iteration, Rust's values are everything but that

I found this to be true of C after many, many years coding in C. I noticed that the first selection of data layout stayed throughout the life of the code (with a lot of tweaks, additions, etc.). But didn't really think that much about it.

Until I started writing code in D. It was easy to change the data layout, and I did for experimenting. For example, changing a reference type to a value type, and vice versa. This was easy in D. It's just too much work in C, so it didn't happen.

The reason is simple:

    p->b
    v.b

To switch between a ref and a value type, you've got to search/replace the -> into ., and the . into ->, and not disturb the dots and arrows of the other types. When dealing with 100,000 lines of code, this is a non-starter.

But with D, both reference and value types are used as:

    p.b
    v.b

making it easy to switch between the two, and also switching function parameters from values back and forth with references.