google / xls

XLS: Accelerated HW Synthesis
http://google.github.io/xls/
Apache License 2.0
1.21k stars 179 forks source link

Add unifying type inference #193

Open cdleary opened 4 years ago

cdleary commented 4 years ago

Right now DSLX type inference is purely deductive (because it was simpler for proof of concept purposes). We should replace this with a unifying type inference algorithm (HM style) when the type inference is finished porting to C++ from Python.

cdleary commented 4 years ago

Note per https://github.com/google/xls/issues/185#issuecomment-725637765 we'd want to make sure shift amounts are inferred with this completed (we expect they would be).

dkillebrew-g commented 3 years ago

You suggested I add this use case as a motivation for this feature:

u32:2 as types::NumWidgets

This is quite a mouthful for the developer who really should just be able to type 2!

Where the type is defined elsewhere, to be something like

pub type NumWidgets = uN[7];