Re: [Haskell-cafe] Type checking the content of a string

Finally, I solved the problem using typeOf instead of interpret: cr :: QuasiQuoter cr = QuasiQuoter { quoteExp = quoteRuleFunc} quoteRuleFunc :: String -> Q TH.Exp quoteRuleFunc s = do res <- runIO $ runInterpreter $ do setImports ["Prelude", "Language.Nomyx.Expression"] typeOf s case res of Right "RuleFunc" -> [| s |] Right _ -> fail $ "Rule doesn't typecheck" Left e -> fail $ show e I don't know really why, but now it's working very well! On Sat, Feb 23, 2013 at 7:56 PM, Daniel Gorín wrote:

Hi Corentin,

I've never used TH, but from what I understand, trying to combine hint and TH would be redundant (even if it worked): whatever String you can evaluate using hint, you can evaluate it directly in TH. Is this not the case?

Cheers, Daniel

On Feb 23, 2013, at 6:53 PM, Corentin Dupont wrote:

...

Hi Daniel, Did you already tried to use Hint in a QuasiQuote? This would come handy to check at compile time the validity of some strings... However I have the error hereunder. The duplicate symbol found in the object file is in fact the first symbol in this file. So I guess GHCi tries to load it twice... Best, Corentin

On Sat, Feb 23, 2013 at 12:03 AM, Corentin Dupont < corentin.dupont@gmail.com> wrote: I'm trying to load my interpreter in the Q monad:

cr :: QuasiQuoter cr = QuasiQuoter { quoteExp = quoteRuleFunc}

quoteRuleFunc :: String -> Q TH.Exp quoteRuleFunc s = do res <- runIO $ runInterpreter $ do setImports ["Prelude", "Language.Nomyx.Rule", "Language.Nomyx.Expression", "Language.Nomyx.Test", "Language.Nomyx.Examples", "GHC.Base", "Data.Maybe"] interpret s (as :: RuleFunc) case res of Right _ -> [| s |] Left e -> fail $ show e

However, I always obtain an error during compilation:

... Loading package XXX ... linking ... done.

GHCi runtime linker: fatal error: I found a duplicate definition for symbol __stginit_ghczm7zi4zi1_DsMeta whilst processing object file /usr/lib/ghc/ghc-7.4.1/libHSghc-7.4.1.a This could be caused by: * Loading two different object files which export the same symbol * Specifying the same object file twice on the GHCi command line * An incorrect `package.conf' entry, causing some object to be loaded twice. GHCi cannot safely continue in this situation. Exiting now. Sorry.

I vaguely understand that the interpreted modules are conflicting with the compiled ones...

On Fri, Feb 22, 2013 at 11:51 PM, Corentin Dupont < corentin.dupont@gmail.com> wrote: Great! That seems very powerful. So you can do what you want during compilation, readin files, send data over the network? Other question, in my example how can I halt the compilation if a test program is wrong?

On Fri, Feb 22, 2013 at 8:30 PM, Francesco Mazzoli wrote: At Fri, 22 Feb 2013 19:43:51 +0100, Corentin Dupont wrote:

...

Hi Adam, that looks interresting. I'm totally new to TH and QuasiQuotes, though. Can I run IO in a QuasiQuoter? I can run my own interpreter.

Yes, you can: < http://hackage.haskell.org/packages/archive/template-haskell/2.8.0.0/doc/htm... .

Francesco