[PRL] values and syntax

[Matthias Felleisen]

Dave, I assume it was obvious that when you design your reduction 
semantics that you may use a syntax that differs from the programmer's 
syntax. I find this less than ideal, and as Riccardo says, some 
theorems become difficult to prove and the semantics is usually 
difficult to manage. For such systems, it is almost always the case 
that :values: isn't a subset of the expressions in the programmer's 
syntax.

-- Matthias