title: What is an FFP machine?
body: <p>In R. Kent Dybvig's paper "Three Implementation Models for Scheme" he speaks of "FFP languages" and "FFP machines". Apparently there is some correlation between FFP machines, and string-reduction on multiple processors.</p>
  
  <p>Googling doesn't really uncover much in terms of explanations or examples.</p>
  
  <p>Can anyone shed some light on this topic?
  Thanks.</p>