Stack safe version

[safareli]

fixes #12

It can be optimize even further but generally i'm satisfied with performance we have now (typelevel/cats#1921)

[safareli]

@natefaubion @paf31 @ethul @garyb I have added tests and i'm confident that it's correct. So this is ready for review. 🎉

[ethul]

Thanks so much for your work on this! Your proposal looks great!

I am still working through the changes, but I am wondering if you happen to have any performance numbers that we can use to compare this to the current implementation and the implementations in #9 and #10.

Would you be willing to include graphs, as a comment in this PR, like the ones in the other PRs? Thanks again!

[safareli]

I remember you had a lib ps-freeap-benchmarks or something but i can't find it any more, do you have a link to it?

[ethul]

Yes! Good call. Are you thinking of this?
https://github.com/ethul/purescript-benchmarks

[safareli]

yes it's that, remembered different name :d

[safareli]

I have added this version of FreeAp to the repo and did benchmarks https://github.com/ethul/purescript-benchmarks/pull/1/files

Now I'm testing only "New" "Day" and "Safe" versions for big inputs (until first two crash :p)

[ethul]

Great! Thanks for doing the benchmarks.

[safareli]

I have added some larger benchmarks ethul/purescript-benchmarks@04a8762

To sum up it has almost the same performance as thunk based version here #9

[ethul]

This all looks great! Thanks again for your work on this PR.