- Glasgow-haskell-users

RE: Empty Datatypes in GHC 5?
by Simon Peyton-Jones 08 Jun '01

08 Jun '01

There isn't such an option at the moment, but it would be simple to add and I've often thoght of doing so. I'm going to be on the train tonight, so you never know... S | -----Original Message----- | From: Ashley Yakeley [mailto:ashley@semantic.org] | Sent: 08 June 2001 01:14 | To: GHC List | Subject: Empty Datatypes in GHC 5? | | | I just joined this list after finally obtaining an i386 | machine primarily | for the purpose of running GHC (I ssh/ftp to it from my Mac). | | A quick question: is there an option to allow empty datatypes in GHC | 5.00? I couldn't see one in the manual. They are useful for type | parameterisation, for instance: | | data Zero; | data Succ n; | | Unfortunately this is contrary to the Haskell Report. | Nevertheless, Hugs | allows it. But GHC, apparently, does not. | | -- | Ashley Yakeley, Seattle WA | | | _______________________________________________ | Glasgow-haskell-users mailing list | Glasgow-haskell-users(a)haskell.org | http://www.haskell.org/mailman/listinfo/glasgow-| haskell-users |

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Empty Datatypes in GHC 5?
by Ashley Yakeley 08 Jun '01

08 Jun '01

I just joined this list after finally obtaining an i386 machine primarily for the purpose of running GHC (I ssh/ftp to it from my Mac). A quick question: is there an option to allow empty datatypes in GHC 5.00? I couldn't see one in the manual. They are useful for type parameterisation, for instance: data Zero; data Succ n; Unfortunately this is contrary to the Haskell Report. Nevertheless, Hugs allows it. But GHC, apparently, does not. -- Ashley Yakeley, Seattle WA

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RE: [GHC5] Creating Socket.PortNumber from Int?
by Simon Marlow 07 Jun '01

07 Jun '01

> Wed, 6 Jun 2001 10:17:34 +0100, Simon Marlow > <simonmar(a)microsoft.com> pisze: > > > Think of it this way: mkPortNumber has been renamed to > fromIntegral, and > > now supports making port numbers from any integral type, > not just Int. > > BTW, why PortNumber is not just Int? It's kept in network byte order. We could make it an Int and do the translation to/from network byte order whenever we need to pass one outside Haskell - I didn't investigate doing it this way, it may or may not be simpler. Cheers, Simon

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Ambiguos Types
by Saswat Anand 07 Jun '01

07 Jun '01

Hi, I have 2 questions: 1- When I load the following module: module Foo() where default (Float) into ghci. 2+3 gives (5::Integer). Should it not give (5.0::Float). Hugs does. 2. class Op a where (%+) :: a -> a -> a instance Op Integer where (%+) = (+) with the above code: (2 %+ 3) should be resolved to Integer type. Could anybody explain why it should not. Thanks, S

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Re: [GHC5] Creating Socket.PortNumber from Int?
by Marcin 'Qrczak' Kowalczyk 06 Jun '01

06 Jun '01

Wed, 6 Jun 2001 10:17:34 +0100, Simon Marlow <simonmar(a)microsoft.com> pisze: > Think of it this way: mkPortNumber has been renamed to fromIntegral, and > now supports making port numbers from any integral type, not just Int. BTW, why PortNumber is not just Int? -- __("< Marcin Kowalczyk * qrczak(a)knm.org.pl http://qrczak.ids.net.pl/ \__/ ^^ SYGNATURA ZASTÊPCZA QRCZAK

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RE: size of interpreted code
by Simon Marlow 06 Jun '01

06 Jun '01

> With ghc-5.00.1, > the compiled Foo.a, Foo.o are each of 7Mb, > ghci -package foo ... > Prelude> :l T_ > loads the interpreted demo examples (importing Foo.o), > and this needs more than 45Mb heap. As we've mentioned before, GHCi has some memory leaks. This is on the list of things to investigate, but we haven't got around to it yet. Cheers, Simon

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size of interpreted code
by S.D.Mechveliani 06 Jun '01

06 Jun '01

Dear ghc-5.00.1, I wonder: is the interpreted code generally expected to be larger than compiled to .o ? I have certain Foo project which under ghc-4.08 had: compiled Foo + compiled demo examples make Foo-Demo.a of 10Mb, and this all load and run on 32Mb RAM computer inside RAM (probably, 15Mb will remain for heap). With ghc-5.00.1, the compiled Foo.a, Foo.o are each of 7Mb, ghci -package foo ... Prelude> :l T_ loads the interpreted demo examples (importing Foo.o), and this needs more than 45Mb heap. Recalling that ghci does not like strict polymorphic data fields, I add that the compiled part has the strict polymorphic fields like D !a !(a -> a), but the interpreted demo programs do not have strict fields. ----------------- Serge Mechveliani mechvel(a)botik.ru

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RE: ghc5 --make question
by Simon Marlow 06 Jun '01

06 Jun '01

> Hi, I'm trying to generate automatic makefiles for my project > using --make. > Unluckily it seems ghc prefers .hs over .hi. The programs > require a fair > amount of separate libraries (Tcl/Tk, a Concurrent Haskell Debugger, a > network wrapper,...) which I currently don't have to care much about: > I just have to provide the corresponding top-level .hi and > some .a-files to > the ghc command line for compiling. > > Is there any way to use ghc --make without having to provide > access to all > of the *source* files and make it use the pre-compiled stuff? Yup, you have to put your pre-compiled stuff in a package. It's a bug in 5.00.1 that it requires the source file; I've fixed it properly in the HEAD as part of the library story, but it almost certainly won't be backported. Cheers, Simon

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RE: [GHC5] Creating Socket.PortNumber from Int?
by Simon Marlow 06 Jun '01

06 Jun '01

> Until 5.00 I could use mkPortNumber to get what I want, i.e. > PortNumber (mkPortNumber port) > Now in 5.01, this function now longer exists. > (PortNumber 5) works, but (PortNumber (5::Int)) does not, so I > have to use "fromIntegral" to get it to work again: > PortNumber (fromIntegral (5::Int)) > > I suppose I'm missing something essential here, as there must be a > better way of doing it when passing a variable of type Int. Think of it this way: mkPortNumber has been renamed to fromIntegral, and now supports making port numbers from any integral type, not just Int. I didin't see the need for a special purpose convesion from Int, when fromIntegral does the job in a much more general way. Besides, using fromIntegral as a general-purpose integral converter is becoming standard practice now that we can optimise it well. Cheers, Simon

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ghc5 --make question
by Volker Stolz 06 Jun '01

06 Jun '01

Hi, I'm trying to generate automatic makefiles for my project using --make. Unluckily it seems ghc prefers .hs over .hi. The programs require a fair amount of separate libraries (Tcl/Tk, a Concurrent Haskell Debugger, a network wrapper,...) which I currently don't have to care much about: I just have to provide the corresponding top-level .hi and some .a-files to the ghc command line for compiling. Is there any way to use ghc --make without having to provide access to all of the *source* files and make it use the pre-compiled stuff? -- Abstrakte Syntaxträume. Volker Stolz * stolz(a)i2.informatik.rwth-aachen.de * PGP + S/MIME

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