add max to gleam/list

[YilunAllenChen]

Inspired by my advent of code 2024 experiences. I often find myself reinventing list.min and list.max with fold and reduce, so I thought maybe it'd be nice to just promote these.

PR Adds list.min and list.max to gleam/list.

Like the name suggests, it returns the max/min element in the list, using the passed in comparator. These are slightly higher level abstractions than reduce as it takes in comparator functions, which can help with ergonomics at many places.

[lpil]

Thank you! Very useful.

I'm wondering if we really need both, given one is the the other inverted. It's be like having a list.filter and a list.filter_not or such.

Are there any other names we might want to consider?

[YilunAllenChen]

Yeah I thought about this, and eventually decided that keeping both is reasonable - here's my train of thoughts

• Having both feels like slight duplication given they are doing quite similar things, just opposite directions, which kind of goes against Gleam's philosophy to keep things simple and having only one way to do things
• However I find it hard to find an intuitive name for this unified function - extreme? Terminal? Or just call it max? I have two problems with that - 1. We do have int.max and int.min and so on, and this creates an assymmetry. 2. I think it's be intuitive to reach for both min and max, rather than doing something like list.extreme(int.compare |> function.flip). I think users will also find it counterintuitive to think about "oh I want the max in this list, so I should reach for extreme". That feels like a bigger violation to Gleam's philosophy to stay friendly haha.

Happy to amend it if you have ideas though! Thanks for the prompt response.

[lpil]

Good reasoning, thank you. Let's move forwards with just max and see how that feels for some time. It's easy to add in future, but it's hard to remove.

[YilunAllenChen]

excellent point that it's hard to remove things! Removed min

[lpil]

Thank you!!