June 2004 - Hat - Haskell.org

Hat bug report: hat-stack fails on simple example
by Fergus Henderson 01 Jul '04

01 Jul '04

Attached is a very simple example program: main calls f, which calls g, which calls h, which calls error. I tried building this with hat ("hmake -hat Foo"), running it ("./Foo") and then using hat-stack ("hat-stack Foo"). But hat-stack reported no useful information. The only output was as follows: | Program terminated with error: | {in h} | Virtual stack trace: source file/line/col | _|_ no source reference | _|_ no source reference ... the same line above, repeated another 62 times ... | _|_ no source reference | _|_ no source reference I also tried using hat-trail, but I couldn't get any useful information out of that either. I am using the latest CVS version of hat with ghc 6.2. Also, hat-trail failed to properly restore the tty state after ":q". -- Fergus J. Henderson | "I have always known that the pursuit Galois Connections, Inc. | of excellence is a lethal habit" Phone: +1 503 626 6616 | -- the last words of T. S. Garp.

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Hat bug report: import Prelude hiding ...
by Fergus Henderson 30 Jun '04

30 Jun '04

Although Hat does support "import Prelude hiding (head)", if you substitute other symbols than "head", in at least some cases it will fail: bash$ cat Bug.hs import Prelude hiding (sin) bash$ hmake -hat Bug hat-trans Bug.hs Wrote Hat/Bug.hs /usr/bin/haskell-compiler -c -package hat -o Hat/Bug.o Hat/Bug.hs Hat/Bug.hs:8: Module `Hat.Prelude' does not export `asin' Fortunately there is a reasonably easy work-around for this one: instead of using "import Prelude hiding ...", you can use "import qualified Prelude" and then explicitly qualify all Prelude symbols. -- Fergus J. Henderson | "I have always known that the pursuit Galois Connections, Inc. | of excellence is a lethal habit" Phone: +1 503 626 6616 | -- the last words of T. S. Garp.

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Hat bug report: Ambiguous occurrence `List'
by Fergus Henderson 30 Jun '04

30 Jun '04

I am trying to get Hat working on a reasonably large and complicated project. Unfortunately it doesn't work. I have cut down the code which triggers the problem to the following simple test case: | bash$ cat Foo/List.hs | module Foo.List where | | class List a b where | foo :: a -> b | | main :: IO () | main = return () | | bash$ hmake -hat Foo/List | hat-trans Foo/List.hs | Creating directories Hat Hat/Foo | Wrote Hat/Foo/List.hs | /usr/bin/haskell-compiler -c -package hat -o Hat/Foo/List.o Hat/Foo/List.hs | | Hat/Foo/List.hs:1: | Ambiguous occurrence `List' | It could refer to either `Hat.Hat.List', imported from Hat.Prelude at Hat/Foo/List.hs:30 | or `Hat.Foo.List.List', defined at Hat/Foo/List.hs:32 I am using hat-2.02.8 with ghc 6.2 on Debian Linux. -- Fergus J. Henderson | "I have always known that the pursuit Galois Connections, Inc. | of excellence is a lethal habit" Phone: +1 503 626 6616 | -- the last words of T. S. Garp.

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Hat bug report: incorrectly lexing "__"
by Fergus Henderson 30 Jun '04

30 Jun '04

Hat mishandles programs containing "__". bash$ cat Foo.hs f :: Int -> Int f __ = 42 bash$ hmake -hat Foo hat-trans Foo.hs Fail: expandTypeSynonym: Int is not a type synonym The problem here seems to be that Hat is lexing "__" as two tokens, rather than one. The Haskell 98 report says | Lexical analysis should use the "maximal munch" rule: at | each point, the longest possible lexeme satisfying the lexeme | production is read. so "__" should be parsed as a single token, not two tokens. Note that in the Haskell 98 grammar, the lexical category "small" includes the underscore character. This bug is very easy to work around, of course. I'm just reporting it for your information. Cheers, Fergus. -- Fergus J. Henderson | "I have always known that the pursuit Galois Connections, Inc. | of excellence is a lethal habit" Phone: +1 503 626 6616 | -- the last words of T. S. Garp.

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Hat bug report: hat 2.02 vs ghc 6.2
by Fergus Henderson 22 Jun '04

22 Jun '04

I tried building Hat 2.02-8 from sources on Debian Linux (testing) using ghc 6.2. It did not compile. I got the following error message: Hat/Foreign/ForeignPtr.hs:89: Variable not in scope: `Foreign.ForeignPtr.foreignPtrToPtr' Hat built OK when configured with "configure --buildwith=ghc5", though. -- Fergus J. Henderson | "I have always known that the pursuit Galois Connections, Inc. | of excellence is a lethal habit" Phone: +1 503 626 6616 | -- the last words of T. S. Garp.

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Support request for compiling hat
by Robert van Herk 18 Jun '04

18 Jun '04

Hi people, As a user of haskell, and as a student in information science at the university of Utrecht, I have been very interested in using hat since a while. However, I cannot get to compile it... First, I tried download the latest releases of ghc, hmake and hat. However, hat refused to compile because it found the ghc version too low (although, in fact, it is probably to new). So, I tried to use the ghc version that the release notes of hat mentioned. However, hmake refuses to compile with this version installed :-(. So, I tried to install BOTH releases of ghc. With this setup, hmake refuses to compile as well... My new approach was to use the latest releases of ghc and hmake again, but try the CVS version of hat. The compiling actually started quite promising, but after a while I got <SNIP> Stop - hmake dependency error. cd src/hattools; make HC=ghc install make[1]: Entering directory `/home/robert/src/hat/src/hattools' hmake -hc=ghc -I. -I/home/robert/src/hat/include -fglasgow-exts -package lang -package util -DUSE_READLINE=1 SrcRefViewer \ -d/home/robert/src/hat/targets/ix86-Linux/obj/hattools Fail: Can't find module System in user directories . . /home/robert/src/hat/include Or in installed libraries/packages at /usr/local/lib/ghc-6.2.1/imports /home/robert/soft/lib/ghc-6.2.1/hslibs-imports/lang /home/robert/soft/lib/ghc-6.2.1/hslibs-imports/util Asked for by: SrcRefViewer.hs Fix using the -I, -P, or -package flags. </SNIP> Could you please help me in trying to compile the hat software? From what I read on the site it is very useful, but I just cannot seem to be able to compile it... Thanx, Robert van Herk

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