March 2005 - Nhc-users

Updates for Mac OS X users using Darwinports
by Gregory Wright 17 Mar '05

17 Mar '05

Hi, Users of Mac OS X/Darwinports will find new portfiles for ghc (ghc-6.4), nhc98 (nhc-1.18) and hugs98 (March 2005 release). The hmake port has been bumped to version 3.10 and a new port of cpphs (version 0.9) has been added. The darwinports system builds from source, although progress is being made on extending it to provide binary packages as well. A new ghc-devel port will be available soon for those who want to live on the bleeding edge. Thanks to Malcolm Wallace for ironing out some last minute issues with nhc98. Best Wishes, Greg Gregory Wright

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Doubts in bytecode
by Arunkumar S Jadhav 17 Mar '05

17 Mar '05

Hello, I've two questions which are unrelated. I'll ask them one by one. Q1) I've this function: myFoo :: (Int -> Int -> Int) -> Int -> Int -> Int myFoo f x y = f (x+y) (x-y) And it compiles to the following bytecode (I've pasted just the byte code part, just ignore other details). bytes2word(NEEDHEAP_I32,PUSH_HEAP,HEAP_CVAL_I3,HEAP_ARG_ARG) , bytes2word(2,3,PUSH_HEAP,HEAP_CVAL_I4) , bytes2word(HEAP_ARG_ARG,2,3,PUSH_P1) , bytes2word(0,PUSH_P1,2,PUSH_ZAP_ARG_I1) , bytes2word(ZAP_ARG_I2,ZAP_ARG_I3,ZAP_STACK_P1,4) , bytes2word(ZAP_STACK_P1,3,EVAL,NEEDHEAP_I32) , bytes2word(APPLY,2,RETURN_EVAL,ENDCODE) Okay, as I've come to understand, this is how things work out. 1. Construct the graph for (x + y) and push its root onto stack. PUSH_HEAP, HEAP_CVAL_I3, HEAP_ARG_ARG, 2, 3 2. Construct the graph for (x - y) and push its root onto stack. PUSH_HEAP,HEAP_CVAL_I4, HEAP_ARG_ARG, 2, 3 3. Now push the first argument onto heap, make top of stack point to it and evaluate it then apply its result to top two elements on stack. (I understand that arguments have to be ZAPped before we start evaluating them, so I know what ZAP is doing here) PUSH_ZAP_ARG_I1, ZAP_ARG_I2,ZAP_ARG_I3,ZAP_STACK_P1,4 ZAP_STACK_P1,3,EVAL,NEEDHEAP_I32, APPLY,2 Now in between all these contents of stack that were pointing to two graphs (i.e x+y and x-y) are being replicated on the stack and then one of the copies (of both the graphs) is being zapped as can be seen from the code snippet below. PUSH_P1, 0, PUSH_P1,2, ,ZAP_STACK_P1,4, ZAP_STACK_P1,3 This has caught me off guard. I just couldn't figure out why is this being done ? i.e Why copy the contents of stack and then zap one of them. Also what all are the uses of ZAP nodes apart from black hole detection. Do ZAP nodes help in garbage collection too ? Now second doubt. Q2) As Malcolm explained in detail this is the purpose of CONSTR macro CONSTR(c,s,ws) Construct a tag (i.e. a header for a data node) where there is a mixture of pointers and basic values amongst the data items I compiled various examples but till now I haven't seen a single example where CONSTR is used for a mixture of pointers and basic values. It has always been for basic values. I'll illustrate with an example. data MyData a = One | Two a | Three a (MyData a) (MyData a) | Four a a a a a intToData :: Int -> MyData Int intToData n = Three 12 (Two 13) One Now the constant table for function "intToData" contains these entries. , CONSTR(2,3,0) , CONSTR(0,0,0) , CONSTR(1,1,0) Clearly, they correspond to the constructors "Three", "One" and "Two" respectively. I expected to see something like CONSTR(2,3, 2) for "Three" constructor because it's second and third field are supposed to be pointers. But this is not the case. Can you please give an example where CONSTR is actually used to construct a mixture of pointer and basic data nodes. Thanks for your patience in going through this. Any help regarding this will be highly appreciated. Regards, ------------------------------------ Arunkumar S Jadhav, Masters Student, KReSIT, IIT-Bombay, India Ph: +91-22-25764967 http://www.it.iitb.ac.in/~arunk ------------------------------------ I exist because I work.

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Build failure of nhc98-1.18 on Mac OS X 10.3.8 with gcc 3.3
by Gregory Wright 14 Mar '05

14 Mar '05

Hi, I've encountered a build failure of nhc98 1.18 on Mac OS X 10.3.8 using Apple's gcc 3.3. The build fails with a bus error, as can be seen in the attached log. GHC is not installed; the build is using gcc. The build was done with 'ulimit -s unlimited' set and also used gnu make 3.79. The build is part of the darwinports infrastructure on Mac OS X, which builds software from source in the manner of the FreeBSD ports collection. The build commands were: CC=gcc ./configure --buildwith=gcc --mandir=/opt/local/share/man ulimit -s unlimited && make Can anyone tell me if I've done something blindingly stupid? Please cc me as I am not subscribed to the nhc lists. Thanks! Best Wishes, Greg Wright

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ANNOUNCE: nhc98-1.18 and hmake-3.10
by Malcolm Wallace 11 Mar '05

11 Mar '05

To complement today's fresh release of ghc-6.4.... ------------------------- nhc98-1.18 + hmake-3.10 ------------------------- http://haskell.org/nhc98 http://haskell.org/hmake We are pleased to announce a new release of the nhc98 compiler and the hmake compilation manager. nhc98 is portable to almost any 32-bit unix-like platform, and can be easily bootstrapped with just a C compiler if no existing Haskell compiler is available. Hmake plays happily with ghc and hbc as well as nhc98. This release is mainly a maintenance refresh, fixing numerous bugs, and adding support for many of the new hierarchical libraries that are also supplied with ghc-6.4 and Hugs. Main bugfixes: * Resolved configuration bugs when using ghc-6.2 and ghc-6.4 with hmake. * Build failures associated with gcc-3.3 and upward have been fixed. Main feature updates: * Supplied with these standard library packages: base, parsec, haskell-src, QuickCheck, HaXml, HUnit, Cabal * FFI: foreign import "dynamic" is now supported, and C header-files named in an import are now respected. * cpphs: The compiler and hmake now use cpphs rather than your C compiler for preprocessing. This removes problems with string gaps, primes in identifiers, and so on. * Source now supplied with a small test suite to help verify whether the compiler works on new platforms. This release of nhc98 has been tested with the following machines and build compilers: ix86-Linux (Slackware 10 and RedHat 7.2 built with ghc-5, ghc-6, hbc, gcc-2.95, gcc-3.3, nhc98) ix86-Cygwin (Windows 2000 built with gcc-3.3, ghc-6) sparc-solaris2 (SunOS 5.9 built with ghc-6, gcc-2.95, nhc98) powerpc-Darwin7 (MacOS X 10.3 using ghc-6, gcc-2.95, gcc-3.3) Credits: Malcolm Wallace (release manager) Ian Lynagh (gcc-3.3 bugfixes, hmake-config add-dyn) Wolfgang Thaller (MacOS gcc-3.3 bugfixes) Simon Marlow (ghc configuration fixes) Sven Panne (warning police, hbc build) numerous library authors, distribution packagers, and bug reporters.

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Data nodes
by Arunkumar S Jadhav 03 Mar '05

03 Mar '05

Hello, As per my understanding following hold true about macroes for data nodes. CONSTR(e, s, ws): This is used to construct header for the data nodes which contain more than one constructors e.g List, Tree etc CONSTRW(s, e) and CONSTRP(s, e) : Are used to construct header for data nodes which contain single constructor e.g Pair. I just wrote a program : ---------------------------------- data MyPair a = ThisPair a a a selectThird (ThisPair 1 x y) = ThisPair 1 1 1 selectThird (ThisPair _ _ y) = ThisPair y y y ------------------------------------ When I saw the corresponding bytecode, I saw (To my surprize) CONSTR(0, 3, 0) being used to construct the data node in the function selectThird (i.e "ThisPair 1 1 1" etc). What is happening here ? If this is the case, then when exactly are the meaning of CONSTR() and CONSTRW(), CONSTRP() Regards, ------------------------------------ Arunkumar S Jadhav, Masters Student, KReSIT, IIT-Bombay, India Ph: +91-22-25764967 http://www.it.iitb.ac.in/~arunk ------------------------------------ I exist because I work.

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GUI ?
by John Velman 01 Mar '05

01 Mar '05

Please excuse me if this is obvious, or if it's obvious how to get one of the GUI packages listed on the Haskell website to work with NHC, but the ones I've looked into all seem (to me) to be dependent on GHC. Is there a GUI package that works with nhc? Thanks, John Velman

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