trying to understand in, inout, and ref...

[Paul Backus]

On Wednesday, 22 January 2020 at 10:49:07 UTC, mark wrote:
> Regarding generate(): allWords should never be changed 
> (generate is called in a loop with the same allWords every 
> time) -- so should it be `in WordSet allWords`?

For parameters that shouldn't be changed, use const. So it should 
be `const WordSet allWords`.

> Regarding update(): ladder and words are both modified in 
> update -- so should they be `ref WordList ladder` and `ref 
> WordSet words`? And if so, do I need to change the update() 
> call in the generate() function?

Yes, they should be `ref`. No, you do not have to change the 
update() call.

> compatibles is (will be) modified in generate() but not in 
> update(), so should it be `in WordSet compatibles`?

It should be `const WordSet compatibles`.