True multi stage Haskell

Shayan Najd sh.najd at
Fri Nov 17 20:04:54 UTC 2017

Hi Tim,

About using GHC as a library module, have you see the ongoing work on
"native metaprogramming" in GHC at

and a child project at

There, online code generation is not of the highest priority, rather we are
trying to open up the compiler from top to down:
making available GHC's AST and then the parser and the typechecker
have priority over the other functionalities down the pipeline (like the
code generator).

> If any one wanted to help with this, that would be great.

I am interested to hear more about the approach you have in mind, and would
be happy to help.


On Fri, Nov 17, 2017 at 6:05 PM, Tim Sheard <sheard at> wrote:

> After many years of hoping someone else would do this, I would like to
> make GHC into a true multi-stage programming language. Here is how I
> thought I might approach this.
> 1) Use the GHC as a library module.
> 2) Use the LLVM backend.
> I have no experience with either of these tools.
> Lets start simple, How would I write functions like
> compile :: String -> IO PtrToLLVMCode  -- where the string is a small
> Haskell program.
> llvmCompile :: PtrToLLVMCode -> IO PtrToMachineCode
> jumpTo:: PtrToMachineCode -> IO ans   -- where ans is the "type" of the
> string.
> Any thoughts on how to get started? What papers to read, examples to look
> at?
> I'd love to move to some more disciplined input type, a sort of (mono)
> typed program
> representation (with similar complexity) to Template Haskell Exp type.
> where (Exp t) is a data structure representing a Haskell program of type t.
> All offers of advice accepted. I'm trying to get started soon, and good
> advice
> about what to avoid is especially welcome.  If any one wanted to help with
> this,
> that would be great.
> Tim Sheard
> _______________________________________________
> ghc-devs mailing list
> ghc-devs at
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <>

More information about the ghc-devs mailing list