Hi, Unfortunately hint does not provide the functionality I require, and from what I remember about hint they also use the GHC API, I guess the problem here is the defaultErrorhandlers that is in initGhcMonad . I've been wondering if I give my own implementation, one that doesn't do any printing at all and reimplement initGhcMonad I can maybe get the desired result but I'm not sure -----Original Message----- From: haskell-cafe-bounces@haskell.org [mailto:haskell-cafe-bounces@haskell.org] On Behalf Of Martin Hilbig Sent: Thursday, May 20, 2010 21:45 To: haskell-cafe@haskell.org Subject: Re: [Haskell-cafe] making the GHC Api not write to stderr hi, i tried this too, but i did not get it. a very nice workaround is to use hint [1]. have fun martin [1]: http://hackage.haskell.org/package/hint On 20.05.2010 20:05, Phyx wrote:

I was wondering how to forcibly quiet down the API. I have a custom handler in place, but when I call the function on failure both my handler gets called and somewhere somehow errors get printed to the stderr, which I really need to avoid.

My current code looks like

getModInfo :: Bool -> String -> String -> IO (ApiResults ModuleInfo)

getModInfo qual file path = handleSourceError processErrors $

runGhc (Just libdir) $ do

dflags <- getSessionDynFlags

setSessionDynFlags $ configureDynFlags dflags

target <- guessTarget file Nothing

addTarget target

setSessionDynFlags $ dflags { importPaths = [path] }

load LoadAllTargets

graph <- depanal [] False

let modifier = moduleName . ms_mod

modName = modifier $ head graph

includes = includePaths dflags

imports = importPaths dflags

dflags' <- Debug.trace (moduleNameString modName) getSessionDynFlags

setSessionDynFlags $ dflags' { includePaths = path:includes

, importPaths = path:imports

}

parsed <- parse modName

checked <- typecheckModule parsed

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Hi, I tried that, setting it to (\_ _ _ _ -> return ()) and it still did the same, also tried setting it to undefined to see whether the code that's printing the error is using it, and it didn't crash So I assume it's not. ----------- *VsxParser> getModInfo True "C:\\Users\\Phyx\\AppData\\Local\\Temp\\tmp5600.hs" "" >> return () C:\Users\Phyx\AppData\Local\Temp\tmp5600.hs:11:13: parse error on input `=' Printf --------- I think parseModule might still have a hardcoded print statement in it. -----Original Message----- From: Thomas Schilling [mailto:nominolo@googlemail.com] Sent: Friday, May 21, 2010 12:53 To: Phyx Cc: haskell-cafe@haskell.org Subject: Re: [Haskell-cafe] making the GHC Api not write to stderr You could try changing the log_action[1] member of the DynFlags. A while ago I turned most printed errors into some form of error message, but I wouldn't be surprised if I missed some places. All output should go through log_action, though, so try changing that to intercept any output. [1]: http://haskell.org/ghc/docs/6.12-latest/html/libraries/ghc-6.12.2/DynFlags.h tml#v%3Alog_action On 20 May 2010 19:05, Phyx wrote:

I was wondering how to forcibly quiet down the API. I have a custom handler in place, but when I call the function on failure both my handler gets called and somewhere somehow errors get printed to the stderr, which I really need to avoid.

My current code looks like

getModInfo :: Bool -> String -> String -> IO (ApiResults ModuleInfo)

getModInfo qual file path = handleSourceError processErrors $

runGhc (Just libdir) $ do

    dflags <- getSessionDynFlags

    setSessionDynFlags $ configureDynFlags dflags

    target <- guessTarget file Nothing

    addTarget target

    setSessionDynFlags $ dflags { importPaths = [path] }

    load LoadAllTargets

    graph <- depanal [] False

    let modifier = moduleName . ms_mod

        modName  = modifier $ head graph

        includes = includePaths dflags

        imports  = importPaths dflags

    dflags' <- Debug.trace (moduleNameString modName) getSessionDynFlags

    setSessionDynFlags $ dflags' { includePaths = path:includes

                                 , importPaths  = path:imports

                                 }

    parsed  <- parse modName

    checked <- typecheckModule parsed

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-- Push the envelope. Watch it bend.

I did some more digging around and it would seem that the error was being printed from the load call (depanal does some parsing ofcourse to find the imports). I managed to silence that using loadWithLogger (const $ return ()) LoadAllTargets (maybe all these loggers should be consolidated). That stopped it from showing part of the error, but can’t figure out what’s showing the module name at the end. “Printf” From: Daniel Peebles [mailto:pumpkingod@gmail.com] Sent: Saturday, May 22, 2010 03:02 To: Phyx Cc: Thomas Schilling; haskell-cafe@haskell.org Subject: Re: [Haskell-cafe] making the GHC Api not write to stderr Have you tried freopen on stderr? On Fri, May 21, 2010 at 8:43 AM, Phyx wrote: Hi, I tried that, setting it to (\_ _ _ _ -> return ()) and it still did the same, also tried setting it to undefined to see whether the code that's printing the error is using it, and it didn't crash So I assume it's not. ----------- *VsxParser> getModInfo True "C:\\Users\\Phyx\\AppData\\Local\\Temp\\tmp5600.hs" "" >> return () C:\Users\Phyx\AppData\Local\Temp\tmp5600.hs:11:13: parse error on input `=' Printf --------- I think parseModule might still have a hardcoded print statement in it. -----Original Message----- From: Thomas Schilling [mailto:nominolo@googlemail.com] Sent: Friday, May 21, 2010 12:53 To: Phyx Cc: haskell-cafe@haskell.org Subject: Re: [Haskell-cafe] making the GHC Api not write to stderr You could try changing the log_action[1] member of the DynFlags. A while ago I turned most printed errors into some form of error message, but I wouldn't be surprised if I missed some places. All output should go through log_action, though, so try changing that to intercept any output. [1]: http://haskell.org/ghc/docs/6.12-latest/html/libraries/ghc-6.12.2/DynFlags.h http://haskell.org/ghc/docs/6.12-latest/html/libraries/ghc-6.12.2/DynFlags.h... tml#v%3Alog_action On 20 May 2010 19:05, Phyx wrote:

I was wondering how to forcibly quiet down the API. I have a custom handler in place, but when I call the function on failure both my handler gets called and somewhere somehow errors get printed to the stderr, which I really need to avoid.

My current code looks like

getModInfo :: Bool -> String -> String -> IO (ApiResults ModuleInfo)

getModInfo qual file path = handleSourceError processErrors $

runGhc (Just libdir) $ do

dflags <- getSessionDynFlags

setSessionDynFlags $ configureDynFlags dflags

target <- guessTarget file Nothing

addTarget target

setSessionDynFlags $ dflags { importPaths = [path] }

load LoadAllTargets

graph <- depanal [] False

let modifier = moduleName . ms_mod

modName = modifier $ head graph

includes = includePaths dflags

imports = importPaths dflags

dflags' <- Debug.trace (moduleNameString modName) getSessionDynFlags

setSessionDynFlags $ dflags' { includePaths = path:includes

, importPaths = path:imports

}

parsed <- parse modName

checked <- typecheckModule parsed

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