June 2006 - Hat - Haskell.org

Missing functions
by Neil Mitchell 30 Jun '06

30 Jun '06

Hi, Now I have Hat on Windows working pretty much, I have tried compiling various programs, unfortunately only very simple examples go through because of missing libraries. I have started a page on the wiki to track the missing dependancies: http://haskell.org/haskellwiki/Hat Thanks Neil

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Hat on Windows, patches
by Neil Mitchell 27 Jun '06

27 Jun '06

Hi, Attached is a patch and some files required to build Hat on Windows. These superceed the ones I sent earlier. With this you get the following tools: hat-trans, exactly as per Linux hat-make, a new tool for windows, think hmake -hat but for Windows (and not as clever) hat-check, exactly as per Linux hat-cover, not very useful unless you do -hion and -hioff since the escape codes are turned off hat-stack, like Linux minus the syntax hilighting hat-observe, lots of escape code garbage, but you can still see the answers The tweaks are: ntohl, not on Windows fopen needs a "b" in the list of options no escape codes, try and eliminate them where possible The new files are: Makefile.bat, the root of the hat repo, serves as a Makefile on Windows - please rename Makefile.bad to .bat, because Gmail won't let me send a "dangerous executable" ntohl.h, for include ntohl.c, for src\hattools, provides the implementation of ntohl HatMake.hs, for src\hattools, the implementation of hat-make Most of the user visible changes are because of the lack of escape codes, which are used in the Linux versions to make a GUI out of the console. The Windows solution would just be to use the standard GUI, and turn the tools into slightly more abstract versions which can have the two interaction methods layered on top of them. I also want to change hat-cover to have an option to output HTML, possible combined with HsColour (modified to be a Haskell library as well as a program) so you can get syntax coloured and nicely highlighted Haskell code. Thanks Neil

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Hat and Windows
by Neil Mitchell 27 Jun '06

27 Jun '06

Hi, I've tried to get Hat compiling on Windows today, and have had some success. I found the following problems and fixes: 1) hat-trans cannot be compiled with ghc -cpp (it breaks on the string gaps), and cpphs can't be used as pgmP as it is. I have submitted a patch for cpphs to make this possible. With this change, hat-trans builds fine for Windows. 2) When running hat-trans, its remarkably painful on Windows, and I got frequent unexplained crashes, but there are a few patches required: Windows does not have ntohl, so I added a specific one for Windows. SIGQUIT does not exist on Windows, I just commented out this line. fopen(file,"w") should be fopen(file,"wb") to use Binary mode under Windows. With these patches, the remaining issues are build issues - I am intending to write a very hacky hat-make which sorts these out, possibly in a Windows specific way, to make it a single hat-make Main command to generate a hat binary. I did not build the hat translated libraries under Windows, I took the Linux versions. With these changes I am able to generate a simple hat file that can be processed by the Linux hat tools properly. Thanks Neil

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Thoughts, Int vs Integer
by Neil Mitchell 26 Jun '06

26 Jun '06

Hi, Often when compiling with Hat I run into the Int vs Integer issue, in fact this is pretty much the biggest problem I have getting hat traces generated. I was considering if there was any possible change that could be performed by Hat to remove this restriction. The best I came up with makes semantic changes to the program, but these changes are "very minimal" at a guess :) The idea basically revolves around "type Int = Integer" - replace all occurances of Int with Integer at the type level, make all functions that operate on Int now operate on Integer instead, and all numeric literals can now become Integer, since there is no Int. There are two semantic changes from this which I have thought of: 1) big_number * 2 will never overflow, which will give a different semantics. Personally this sounds like a good idea, and having a hat-overflow tool to detect when an Integer goes above 2^31 would probably be a useful addition. I don't consider this change to be all that bad, since its compatible with the Haskell98 report (I think). 2) More seriously, type classes will lead to different code being invoked. For example while 0 == 0 might have invoked Int equality now it will invoke Integer equality. My guess is that if there is a program where the type class for Int is not a subset of the behaviour of that for Integer, its very weird and confusing and probably buggy. The changes to the generator that would need to be made are (as far as I can tell) as follows: * Replace all occurances of Int with Integer * Make all numeric literals 0 :: Integer * On encountering a typeclass if there existing an instance for one of Int or Integer, then use that one. If instances exists for both Int and Integer then throw away the Int version. For a prototype, allow-undecideable-instances & allow-overlapping-instances should handle this automatically. * Any primitive operations that are performed on Int and not Integer would need to be worked around, probably on a case by case basis, but this should be a small number. Comments or thoughts? Thanks Neil

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Problem building hat
by Klaus Ostermann 21 Jun '06

21 Jun '06

Hi there, I am trying to build hat using ghc6.4.1 with windows/cygwin. I also tried nhc, but with the same error. ./configure works fine, but "make" exits with the following error: Warning: package(s) base not available (according to ghc-pkg) Can't find module lang in user directories . . ../compiler98 Or in installed libraries/packages at Asked for by: commandline Fix using the -I, -P, or -package flags. Stop - hmake dependency error. make[1]: *** [c:/dev/hat-2.04/lib/ix86-CYGWIN_NT-5.1/hat-trans.exe] Error 255 make[1]: Leaving directory `/cygdrive/c/dev/hat-2.04/src/hattrans' make: *** [targets/ix86-CYGWIN_NT-5.1/hat-trans-ghc] Error 2 Any ideas? Thanks, Klaus P.S.: It would be great if you could add binaries to your download section

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