September 2002 - Hugs-Bugs

toUpper bug
by Martin Norbäck 12 Sep '02

12 Sep '02

The Haskell 98 Library Report says: Function toUpper converts a letter to the corresponding upper-case letter, leaving any other character unchanged. However, there are two lower case letters that doesn't have the corresponding upper case letter in hugs (since it's only iso-8859-1 yet). In hugs: toUpper 'ÿ' = 'ß' toUpper 'ß' = '¿' but they should be unchanged (they have no corresponding upper-case letter). Regards, Martin -- Martin Norbäck Safelogic AB martin.norback(a)safelogic.se Stena Center 1C +46 (0)31 772 81 70 S-412 92 GÖTEBORG http://www.safelogic.se SWEDEN

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hiding (Stuff(..))
by Ross Paterson 11 Sep '02

11 Sep '02

Hugs accepts the following modules: module A(Stuff(Foo, Bar)) where data Stuff = Foo | Bar module B(Stuff) where import A hiding(Stuff(..)) but Stuff should also be hidden.

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hugs98: configure Linuxism
by Volker Stolz 06 Sep '02

06 Sep '02

Hi, there's a Linuxism in hugs98-Dec2001/src/unix/configure: if (test "`basename ${YACC}`x" == "byaccx"); then echo "Found 'byacc', but the Hugs98 parser is incompatible with it." The test should be one simple "=" for string equality. This will make configure trip e.g. on FreeBSD (though it'll do no harm -- yet). Regards, Volker -- plonk :: m a -> m () http://www-i2.informatik.rwth-aachen.de/stolz/ *** PGP *** S/MIME

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Unexpected signal on hclosing stdout twice
by Alastair Reid 05 Sep '02

05 Sep '02

Running 'hClose stdout' twice in a row causes Hugs to abort: Prelude> :l IO Reading file "/home/reid/local/lib/hugs/lib/IO.hs": Reading file "/home/reid/local/lib/hugs/lib/Ix.hs": Reading file "/home/reid/local/lib/hugs/lib/IO.hs": Hugs session for: /home/reid/local/lib/hugs/lib/Prelude.hs /home/reid/local/lib/hugs/lib/Ix.hs /home/reid/local/lib/hugs/lib/IO.hs IO> hPutStr stdout "abcde" >> hClose stdout abcde IO> hPutStr stdout "abcde" >> hClose stdout Unexpected signal -- Alastair Reid alastair(a)reid-consulting-uk.ltd.uk Reid Consulting (UK) Limited http://www.reid-consulting-uk.ltd.uk/alastair/

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local qualified names
by Iavor S. Diatchki 04 Sep '02

04 Sep '02

hi, here is a module system bug: module List where data T a = Nil | Cons a (T a) nil :: List.T a nil = T.Nil ERROR "test.hs":5 - Undefined type constructor "List.T" (and also the value constructor is not defined). one should be able to refer to local names with their qualified names. this is good for documentation purposes, when one programs in a certain style (1 datatype/module, and it is always called T). it is also important when combined with the "lazy name clash" feature of the haskell module system to resolve conflicts. bye iavor -- ================================================== | Iavor S. Diatchki, Ph.D. student | | Department of Computer Science and Engineering | | School of OGI at OHSU | | http://www.cse.ogi.edu/~diatchki | ==================================================

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transitive imports & hiding
by Ross Paterson 04 Sep '02

04 Sep '02

With these modules: module A(function, Class(method)) where function = id class Class a where method :: a module B(function, Class(..)) where import A module C where import B hiding (function) f = method hugs C.hs yields ERROR "C.hs":3 - Undefined variable "method"

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