Vector/Array support?

[Magalame]

Hi,

Roc has a lot of features I'm keen to try out. I'm also curious to know practical it is for dealing with linear algebra so I was wondering if vectors/matrices are supported?

My second question concerns how Roc deals with mutation. As I understand it, the optimisation allowing for in-place mutation relies on the mutated variable not being referenced to later in the program. In programs dealing with large matrices, it'd be very convenient to ensure that mutation is always in place, so are there any features of the language to prevent a variable from being re-used? For example Rust has the notion of ownership.

[Anton-4]

Hi @Magalame,

if vectors/matrices are supported?

We currently have no specific optimizations for vectors, matrices, and linear algebra in general. With Roc's new compiler we will support "overloading of functions" with what we call static dispatch. So if you make your own matrix type, you will be able to write a * b to do matrix multiplication.

so are there any features of the language to prevent a variable from being re-used?

There are no official plans around that yet but some options were discussed here:
#ideas > assertUnique function. @ 💬

[Magalame]

Thanks for the quick answer! I note the explicit desire not to reproduce Rust's ownership system, is it for the sake of simplicity?

[lukewilliamboswell]

@Magalame there is a more comprehensive answer to this question over in zulip https://roc.zulipchat.com/#narrow/channel/231634-beginners/topic/Question.20from.20GH.20-.20Mutation.20in.20Roc/near/527322134

[dezren39]

#beginners > Question from GH - Mutation in Roc @ 💬

Kiryl Dziamura: Ok, I probably just don't understand the downside of (elem; 12) syntax
Richard Feldman: hm, I guess if that were just syntax sugar for the same tuple elem type repeated that many times, that would be fine
Brendan Hansknecht:

Yeah, I think sugar on top of homogeneous tuples could be enough. We don't need that much. Creation with default value, querying with a runtime determined index, copying to/from lists, being able to query the size at runtime, iteration.

At the same time, I still think we could force everything through an allocating list until a few users come to us with performance problems we can't resolve without stack allocated lists.