Duncan Coutts wrote:
Sorry, I've been slow in replying.
No problem. I appreciate your response.I realise I am also slow in replying but I only seem to have time at weekends these days.
I tend to be a bit reluctant to expose more internal functions to Setup scripts. It means there's more stuff we can't change without breaking packages.
In this case I'm not convinced you need it, running your Setup.hs I get duplicate reports for the programs in question because configure already reports them. The extra warnings are fine of course.
Obviously, I don't want duplicate reports. But I would like finer control of messages. I think I have a valid requirement. What do you suggest? Cutting and pasting code seems worse than exposing a function. Or maybe something else could be beefed up to allow the user (i.e. me) finer control of warning messages? I did think the interface was slightly clunky but it's probably me mis-using it. I seemed to have to specify things twice. Once here:
perHooks = simpleUserHooks { hookedPrograms = [ simpleProgram "pdflatex" , simpleProgram "asn1c" ] , postConf = perPostConf }
And then because I wanted finer control over the warning messages I specified things again. I suspect I could get rid of hookedPrograms (and possibly simpleUserHooks). But then I need a function to display the results and reportProgram almost does the job (it's just not exposed).
perPostConf :: Args -> ConfigFlags -> PackageDescription -> LocalBuildInfo -> IO () perPostConf a cfs pd lbi = do let v = fromFlagOrDefault normal (configVerbosity cfs) pdfSP = simpleProgram "pdflatex" mPdf = lookupProgram pdfSP (withPrograms lbi) asn1cSP = simpleProgram "asn1c" mAsn1c = lookupProgram asn1cSP (withPrograms lbi) cSP = simpleProgram cCompilerName mC = lookupProgram cSP (withPrograms lbi) case mPdf of Nothing -> warn v "Full documentation cannot be built without pdflatex" >> return () Just _ -> do reportProgram v pdfSP mPdf return () case mAsn1c of Nothing -> warn v "Full inter-operability testing cannot be performed without asn1c" >> return ()
Possibly a bit more explanation in the documentation (http://haskell.org/ghc/docs/latest/html/libraries/Cabal/Distribution-Simple....) would help people like me. Something like "If you want to check for programs then use hookedPrograms and you will get the cabal standard messages. If you want finer control then use lookupProgram and reportProgram e.g. ..." Dominic.