Stephen Chung

Also, I see that you have replaced `map_or` etc. with `if let`, and replaced iterators with `for` loops. Theoretically speaking, these two styles should compile down to very similar machine...

> In the experience I had when optimizing it, I found that replacing things such as ``map_or`` reduced function calls. I just have a regular release build, so I'm unsure...

Another issue with using the `HashMap` is that it is very slow to get a list of all cells in a row or column, operations that are common. Moreover people...

Just build two separate indices with maybe mapping row and column to lists of cells. They can then help greatly with searching and in order iteration. If you use `BTreeSet`s...

> [@iancormac84](https://github.com/iancormac84) is there an advantage to using `IndexMap` over adding the indices as suggested by [@schungx](https://github.com/schungx)? `IndexMap` in the back is just an index pointing to slots in a...

> Ok thanks for explaining. I guess given that. Adding the index accomplishes the same thing with the bonus of having them be "naturally" ordered. Correct. Using a `BTreeSet` or...

> How would BTreeMap work though? Ah, you're right. `BTreeMap` won't work because the index needs to be unique. > In the past I've used structures similar to BTreeMap> You...

Here is the PR: https://github.com/MathNya/umya-spreadsheet/pull/273

Wow, I'll need some time to look thru this, but great work! Actually a lot of people have asked for it, but I'm not quite sure named arguments is a...

> User defined functions that overload a function name and match from the parameters are now always preferred over functions that match because of default parameters. I assume you enhance...