Unable to make args mandatory

[toothbrush]

Hello! Great library, thank you. I'm struggling though, and i feel like i'm doing what the docs say i should do. I'm using version cmdargs-0.10.12.

So i have this bit of code:

data DiaspecCompiler = Pretty { inFile :: FilePath
                              , outFile :: Maybe FilePath}
                     | Racket { inFile :: FilePath
                              , outFile :: Maybe FilePath}
                     | Java   { inFile :: FilePath }
                     deriving (Show, Data, Typeable)

pretty = Pretty { inFile = def &= args &= typFile
                , outFile = Nothing &= typFile} 

java   = Java   { inFile = def &= args &= typFile }

racket = Racket { inFile = def &= args &= typFile
                , outFile = Nothing &= typFile} 

mode = cmdArgsMode $ modes [racket, java, pretty]

main :: IO ()
main = do
  opt <- cmdArgsRun mode

When i run ./mything --help i get the following output, though:

The diaspeccompiler program

diaspeccompiler [COMMAND] ... [OPTIONS]

Common flags:
  -? --help          Display help message
  -V --version       Print version information

diaspeccompiler racket [OPTIONS] [FILE]

  -o --outfile=FILE

diaspeccompiler java [OPTIONS]

  -i --infile=ITEM 

diaspeccompiler pretty [OPTIONS]

  -i --infile=ITEM 
  -o --outfile=ITEM

Which looks like nonsense to me. I expect each mode to have a mandatory FILE argument at the end, since all modes must operate on an input file. Where is the -i option coming from? Am i doing something brain-dead?

[ndmitchell]

Try setting {-# OPTIONS_GHC -fno-cse #-} at the top of the file - does that fix it?

[toothbrush]

That's pretty cool, it seems better now, thanks! I'll get back to you if my more complex case also fails (the one i'm working towards).

[ndmitchell]

This issue tends to crop up more with small test cases than with real examples, but the same fix should work. Please let me know if anything else causes you problems.

[dan-t]

Hi Neil,

I think, that I got a pretty similar problem:

data Args =
   ...
   | Dump { output     :: String
          , cabalFiles :: [FilePath]
          }
   deriving (Data, Typeable, Show, Eq)

dumpArgs :: Args
dumpArgs = Dump
   { output     = def &= explicit &= typ "FILE" &= name "output" &= name "o"
                      &= help "Save libraries with lower bounds to file, if empty, then it's written to stdout."
   , cabalFiles = def &= args &= typ "CABAL_FILE"
   }

 $> cabal-bounds dump --help
 cabal-bounds dump [OPTIONS]

 Flags:
   -o --output=ITEM            Save libraries with lower bounds to file, if
                               empty, then it's written to stdout.
   -c --cabalfiles=CABAL_FILE
 Common flags:
   -h --help                   Display help message
   -v --version                Print version information
      --numeric-version        Print just the version number

The problem is, that I've no idea when this broke, because it certainly worked at the beginning.

Yes, adding {-# OPTIONS_GHC -fno-cse #-} solves the issue, but it certainly doesn't feel like the Haskell way.

Greetings, Daniel