He&#x27;s probably referring to SPJ&#x27;s work on the spineless tagless G-machine [1].<p>In truth, though, I think trying to incorporate Call-By-Push-Value into Haskell would radically change the language unless there&#x27;s some research in type theory that allows for the implicit Call-By-<i>Need</i> nature of Haskell to be extended into a form that can accommodate CBPV, which itself explicates a kind duality between Call-By-Name and Call-By-Value.<p>If advancements have been made here, I&#x27;d love to hear about it.<p>[1] <a href="http:&#x2F;&#x2F;research.microsoft.com&#x2F;apps&#x2F;pubs&#x2F;default.aspx?id=67083" rel="nofollow">http:&#x2F;&#x2F;research.microsoft.com&#x2F;apps&#x2F;pubs&#x2F;default.aspx?id=6708...</a>