Olle Fredriksson

Joined to follow @plt_borat. Compilers and functional programming.

[Olle Fredriksson @ollfredo]

@typeswitch Branch displacement optimization, deciding whether a relative jump is short enough to use the smaller instruction encoding, is also messy fun.

[Olle Fredriksson @ollfredo]

@typeswitch I ended up going through a monoidal description record in my assembler because of the damn prefixes. Too much back and forth to go directly to bytes cleanly.

[Olle Fredriksson @ollfredo]

@GabriellaG439 Have you seen https://t.co/XP8ssvG8MA?

[Olle Fredriksson @ollfredo]

@luctielen @OlleF That looks very clean. Nicely done.

Btw, you got the wrong Olle on here. :)

[Olle Fredriksson @ollfredo]

@brendanzab @kamatsu8 @wenkokke @cyberglot @jonmsterling Assuming that the implementations and formalisations are distinct... :)

[Olle Fredriksson @ollfredo]

@brendanzab @kamatsu8 @wenkokke @cyberglot @jonmsterling Yes: Sixty does NbE with De Bruijn indices in the syntax and fresh vars in the domain to avoid shifting during pattern matching elaboration, which can make modifications to the middle of the context. But I guess implementations might have different tradeoffs than formalisations.

[Olle Fredriksson @ollfredo]

@julepaj samma fast "melon"

[Olle Fredriksson @ollfredo]

@brendanzab @andrasKovacs6 @jonmsterling It doesn't evaluate further.

[Olle Fredriksson @ollfredo]

@brendanzab @andrasKovacs6 @jonmsterling There it is! Also note that the sentinel https://t.co/1t9bSyTEtG unifies with anything without error in an attempt not to get cascades of errors due to errors.

[Olle Fredriksson @ollfredo]

@brendanzab @andrasKovacs6 @jonmsterling No, just for better inference. Errors in elaboration result in sentinel error terms to be able to keep going.

[Olle Fredriksson @ollfredo]

@brendanzab @andrasKovacs6 @jonmsterling Sixty does postponing!

[Olle Fredriksson @ollfredo]

@jaredweakly @Iceland_jack @JulienTruffaut Careful, those two are not the same.

[András Kovács @andrasKovacs6]

It's a bit crude now, but if you want the fastest parser library in Haskell, which is a) on Hackage b) can be used for real-world programming language parsing with reasonable effort, see this: https://t.co/188Aubexvs

[Olle Fredriksson @ollfredo]

@tomjaguarpaw That's funny. SQL LIMIT and OFFSET was exactly the context that I found this in: https://t.co/l52XpjIBSQ

[Olle Fredriksson @ollfredo]

Has anyone seen this monoid with a cute action on lists before?

empty = (∞, 0)
(t₁, d₁) ⋄ (t₂, d₂) = (min t₁ (t₂ - d₁), d₁ + d₂)
act (t, d) = take t . drop d

[Olle Fredriksson @ollfredo]

act (t₁, d₁) . act (t₂, d₂) =
take t₁ . drop d₁ . take t₂ . drop d₂ =
take t₁ . take (t₂ - d₁) . drop d₁ . drop d₂ =
take (min t₁ (t₂ - d₁)) . drop (d₁ + d₂) =
act (min t₁ (t₂ - d₁), d₁ + d₂) =
act ((t₁, d₁) ⋄ (t₂, d₂))

[Performance Summit @perfsummit1]

London Perf Summit #2 is almost here ! Meet Olle Fredriksson (@ollfredo) as he presents how to build real-time tooling and incremental compilers using a build system library called Rock
#londonperfsummit Sign-up here: https://t.co/caX4tmwQOQ
https://t.co/gcUTm2p5VC

[Olle Fredriksson @ollfredo]

@rob_rix Lists seem quite hard to beat for performance at small sizes. I have some benchmarks here: https://t.co/4uJWiEKP9L

[Olle Fredriksson @ollfredo]

@runarfu Tror syrran är på jakt efter ett, så kanske. Mer detaljer?

[Olle Fredriksson @ollfredo]

My best and most important work