problem running wxHaskell (Windows)

Question

The page: (http://en.wikibooks.org/wiki/Haskell/GUI) describes that to run wx code, one can install wx and then one must "register wxHaskell with GHC" - but I think the binary installer of wxHaskell (http://wxhaskell.sourceforge.net/download.html) does that automatically?

I installed wx-config, and then wxPack, and wxHaskell. and then did cabal install of wx and wxcore. I am running some wx demos from Leksah, which seem mostly good - but they had some weird errors (I found an alleged solution to that: "wxhaskell-labels-cant-display-full-text"), but I wanted to try some things just from GHCi.

I try to run their simple demos, and the the errors:

D:\csPlangs\Haskell\play>ghci -package wx wxGui1.hs
GHCi, version 7.0.3: http://www.haskell.org/ghc/  :? for help
Loading package ghc-prim ... linking ... done.
Loading package integer-gmp ... linking ... done.
Loading package base ... linking ... done.
Loading package array-0.3.0.2 ... linking ... done.
Loading package stm-2.2.0.1 ... linking ... done.
Loading package bytestring-0.9.1.10 ... linking ... done.
Loading package containers-0.4.0.0 ... linking ... done.
Loading package Win32-2.2.0.1 ... linking ... done.
Loading package filepath-1.2.0.0 ... linking ... done.
Loading package old-locale-1.0.0.2 ... linking ... done.
Loading package old-time-1.0.0.6 ... linking ... done.
Loading package directory-1.1.0.0 ... linking ... done.
Loading package transformers-0.2.2.0 ... linking ... done.
Loading package mtl-2.0.1.0 ... linking ... done.
Loading package parsec-3.1.1 ... linking ... done.
Loading package time-1.2.0.3 ... linking ... done.
Loading package wxdirect-0.12.1.4 ... linking ... done.
Loading package wxcore-0.12.1.7 ... ghc.exe: stdc++: The specified module could
not be found.
<command line>: can't load .so/.DLL for: stdc++ (addDLL: could not load DLL)

And also the [interesting] error:

*Main> q

<interactive>:1:1: Not in scope: `q'
*Main>
ghc.exe: panic! (the 'impossible' happened)
  (GHC version 7.0.3 for i386-unknown-mingw32):
        thread blocked indefinitely in an MVar operation

Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug

Answer 1

It appears to be a known problem with the combination of wxHaskell, GHCi, and Windows. From http://www.haskell.org/haskellwiki/WxHaskell/Quick_start

On Windows 7, ghci will complain "can't load .so/.DLL for: std c++ ...". But ghc --make Hello.hs; Hello.exe on the command line works well.

So, you can compile your code. You just can't run it through the interpreter.