[Haskell-cafe] questions about core

[Matt Roberts]

Hi all,

I am trying to get a deeper understanding of core's role in GHC and  
the compilation of functional languages in general.  So far I have  
been through
  - The hackathon videos,
  - "A transformation-based optimiser for Haskell",
  - "An External Representation for the GHC Core Language (DRAFT for  
GHC5.02)", and
  - "Secrets of the Glasgow Haskell Compiler inliner".

and I am still a bit hazy on a few points:
  - What role do *the semantics* of core play (i.e. how and where are  
they taken advantage of)?
  - Exactly what are the operational and denotational semantics of core?
  - The headline reasons (and any other arguments that emerge) for  
having core *and* stg as separate definitions.

I have an intuition on a few of these points, but I would love  
something concrete to latch on to.

Thanks

Matt R