Laziness in Haskell — Part 3: Demand

soltech, 8 months ago

This video series is really great!

jaror, 8 months ago

I think pseq does have that "thunk forcing" behavior:

import GHC.Conc (pseq)

val :: Int
val = let x = error "x"
          y = error "y"
      in y `pseq` (x + y)

main = print val

I believe this is guaranteed to show the y error and not the x error.