RE: GHC internals

That's not really true though. The compiler implements beta-reduction; and inlining; and directly implements the "Push" rules in exprIsConApp_maybe. S | -----Original Message----- | From: Richard Eisenberg [mailto:eir@cis.upenn.edu] | Sent: 29 April 2013 14:30 | To: Simon Peyton-Jones | Cc: 'Norman Ramsey'; ghc-devs@haskell.org; Simon Marlow | Subject: Re: GHC internals | | It's true that the document in GHC doesn't include operational | semantics, but that's because GHC doesn't ever really implement a | concrete operational semantics for Core, at least that I'm aware of. | There are various places that a certain operational semantics is | assumed. However, I don't think there's one place that really states the | semantics in any concrete way. The goal of the document you attached is | to have an easy-to-read and easy-to-maintain version of Core, with a | direct connection to the implementation. With the operational semantics | never stated, including those rules seemed to go against that goal. | | That said, it wouldn't be hard for me to imagine an operational | semantics and add it to the document -- I just don't know how I would | check my imagined version against the implemented one. | | Richard | | On Apr 29, 2013, at 8:38 AM, Simon Peyton-Jones | wrote: | | > Norman | > | > | - Is there anything published about the implementation of GHCi? | > | Or perhaps something on the Developers' Wiki that explains how | it works? | > | > If you mean the details of bytecode compilation and the bytecode | interpreter, I'm really not sure that there is. That's bad; there | should be. I'm ccing Simon M in case he knows of something. | > | > | - What is the best paper (or papers) to consult on the semantics | > | of GHC core? | > | > Many of these papers | > http://research.microsoft.com/en-us/um/people/simonpj/papers/ext-f/ | > give syntax, static semantics, and operational semantics of Core. | > | > Moreover, Richard Eisenberg has developed a specification of the Real | Core in GHC, kept in the source tree in docs/core-spec | > | > I enclose a typeset version. | > | > Sadly it doesn't include operational semantics, but I don't think | that'd be hard to add, would it Richard? The papers on the above link | give several versions of the operational semantics, which is largely | straightforward. | > | > Simon | >