linear-base VS linear-builder

lol no Data.Dough.Destination

Thanks for your interest in linear types. The sort of overarching answer is that the Covid crisis has put a serious wrench in our plans. There has been very little progress on the implementation in the past 2 years, I'm afraid. I hope to slowly pick up the pace again this year. But I make no promise as to specific plans just yet. When we have more visibility, we will publish a roadmap. This is not to say that nothing has happened at all: linear-base is getting a pretty significant release any day now, David Feuer (no affiliated with Tweag) has created linear-generics, an implementation of Generic which is compatible with linear types (there is a surprisingly subtle issue with Generic1, in particular, that I don't understand very well, so won't try to explain), we co-wrote two academic articles as well.

See here for a linear quicksort implementation.

Handle is defined in terms of UnsafeResource (in linear-base). This is where the linearity checking "stops". If you pattern match an UnsafeResource then you have to make sure that you correctly close/free it. Luckily, this only has to be implemented once in an internal module and is not exported in the public interface.

The optics sublibrary is not very developed yet. Because our arrays, which are one of the principal use-case, require a special kind of lens which we haven't managed to produce without too much code duplication yet. The design space is discussed in this issue.

So to write a function f :: a %1 -> () you have to traverse the whole datatype a, see the Data.Unrestricted.Internal.Consumable and Data.Unrestricted.Internal.Instances, which introduces a type class consumable which implements exactly this functionality.

Trying to run empty Ur shouldn't typecheck, because the Ur constructor is not linear. This seems to be an idiom used in other places of linear-base.

Another interesting area of performance optimisation is linear types. It's already possible to take advantage of them in libraries https://github.com/Bodigrim/linear-builder with real world performance gains and in the future in GHC. More about this here https://www.reddit.com/r/haskell/comments/5z6mxb/linear_types_make_performance_more_predictable/?utm_source=share&utm_medium=ios_app&utm_name=iossmf

I've been toying with a strict Text builder, backed by linear types, and benchmarks look very good, up to 10x faster than Data.Text.Lazy.Builder. I'd like to collect more feedback before releasing it, so I'd appreciate people taking a look at https://github.com/Bodigrim/linear-builder/ or rendered haddocks.

I've been playing around with linear types, attempting to design a strict Text builder. Admittedly I know too little about both topics, so I'd appreciate some feedback about my ramblings, because benchmarks look suspiciously good: https://github.com/Bodigrim/linear-builder/