Help needed with a compiling error

[HP Wei]

compiler: nhc98-1.18 on Sun sparc machine
code-to-compile: the  one near the end of this web page:
           http://cgi.cse.unsw.edu.au/~dons/blog/2006/12/18

[ I cut-and-paste it into a file called cat.hs ]

command invoked:
   nhc98 -o cat cat.hs
   nhc98 -package base -o cat cat.hs

   [ both give the same result. ]

The last line of total 4 lines of output looks like:

Fail: superclassesI InfoUsedClass 52 [(Type class, Text.Printf.PrintfArg,
                                      "ftnirP.txeT", 52:11-52:19)] ...

Could someone tell me what I should do to fix the problem ?

Note: the same code can be compiled with ghc6.8.2
      [ but I have to repalce withFile with withFile1 in cat.hs ].
     
      I am using nhc98 so that the binary-code generated
      can be small.

Thanks
HP



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[Malcolm Wallace]

HP Wei <hp@...> wrote:

> Fail: superclassesI InfoUsedClass 52 [(Type class, Text.Printf.PrintfArg,
>                                       "ftnirP.txeT", 52:11-52:19)] ...

nhc98 is confused about whether the classes defined in Test.Printf are
necessary or not.  There is a workaround: explicit imports.  Replace

    import Text.Printf

with

    import Text.Printf (IsChar(),PrintfArg(),printf)

and everything will work OK.

Regards,
    Malcolm
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