- Hugs-Users - Haskell.org

Re: [Hugs-users] hugs docs
by dfeustel＠mindspring.com 19 Dec '06

19 Dec '06

Am Dienstag, 19. Dezember 2006 02:41 schrieb Dave(a)haskell.org, > Feustel(a)haskell.org: > > What software is used to convert the .xml and .sgml files in the > > Hugs docs directory to something (pdf?) readable? > > {docbook,db}2{html,dvi,pdf,ps}, depending on what should be converted and > which tools are available. In your case: Either docbook2pdf or db2pdf. > > For GHC we use a combination of xsltproc/fop/xmltex/dvips. > > Cheers, > S. Not all of the software you mention is installed on my computer. I will google for the missing programs. Many Thanks for the info, Dave Feustel

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hugs docs
by unknown＠example.com 19 Dec '06

19 Dec '06

What software is used to convert the .xml and .sgml files in the Hugs docs directory to something (pdf?) readable? Thanks, Dave Feustel

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Pocket Guide to Haskell
by unknown＠example.com 17 Dec '06

17 Dec '06

Is there available an O'Reilly-like Pocket Guide to Haskell that lists all the builtin functions and those defined in Prelude.hs? Thanks, Dave Feustel

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Re: [Hugs-users] Start hugs without loading Prelude.hs?
by dfeustel＠mindspring.com 11 Dec '06

11 Dec '06

> On Mon, Dec 11, 2006 at 04:23:21PM +0000, dfeustel(a)mindspring.com wrote: > > > [BTW, your mailer is mangling From: lines] > > > > Thanks for the tip. What's getting mangled? > > When you start a new thread, your From: line is > > > One of your replies to Mark Hills put his address into the From: line. I am no longer using a standard email program. When I reply to a message, I contstruct the reply by manually editing the message being replied to. I make mistakes when I do that. One of the mistakes I make is forgetting to update the From: address. I'll try to be more careful. > > I'm trying to understand what primitive operators are built into hugs > > that are then used to load the Prelude. (I'm a bottom-up type of person). > > I don't think that a bottom-up approach that goes through Hugs is the > best way to learn Haskell (not that going through a compiler written > in Haskell will be any better). You're better off taking the Haskell > 98 Report as the baseline. That is my plan. I expect to buy copies of the revised report and the Haskell Road to Logic,... book I got through interlibrary loan. The revised report is available online, but I find reading a physical book handy when I want to take a break from the computer. > > > (If you still have that Prelude.hs you copied in the current directory, > > > you should remove it.) > > > > What I still don't understand is why that file being present affects > > the way hugs runs when hugs says it is ignoring the file. > > The explanation is in the above messages of Mark Hills and myself; I > can't think of another way to express it. Basically you put an internal > Hugs module where it wasn't expected. Just don't do that. At some point I am going to fix that problem in my copy of hugs. Dave Feustel

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Re: [Hugs-users] Start hugs without loading Prelude.hs?
by dfeustel＠mindspring.com 11 Dec '06

11 Dec '06

> [BTW, your mailer is mangling From: lines] Thanks for the tip. What's getting mangled? > On Mon, Dec 11, 2006 at 04:08:30PM +0000, Dave(a)haskell.org wrote: > > I am now reading the Haskell 98 Revised Report. > > Good plan. Reading chapters 6, 7 and 8 of the Report (not necessarily > in that order) is a better way of getting acquainted with the Prelude > than reading Prelude.hs from the Hugs source. I am also reading the gentle intro to Haskell. I find the revised Haskell 98 report to be the clearest explanation (until MEGO and I have to take a break). Last night MEGO occurred when I started reading about patterns. I'll try again later today. > > As I get a better understanding of the Prelude, > > I am wondering if there is a way to run hugs > > without the prelude file being loaded. Is that possible? > > You can't prevent it being loaded, but you can hide all the names it > defines by writing a module > and loading that. (Not sure why you'd want to do that, though.) I'm trying to understand what primitive operators are built into hugs that are then used to load the Prelude. (I'm a bottom-up type of person). > (If you still have that Prelude.hs you copied in the current directory, > you should remove it.) What I still don't understand is why that file being present affects the way hugs runs when hugs says it is ignoring the file. It's looking to me like Haskell/Hugs98 is shaping up to be my next big self-education project. Dave

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Start hugs without loading Prelude.hs?
by unknown＠example.com 11 Dec '06

11 Dec '06

Hi! I am now reading the Haskell 98 Revised Report. As I get a better understanding of the Prelude, I am wondering if there is a way to run hugs without the prelude file being loaded. Is that possible? Thanks, Dave Feustel

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Re: [Hugs-users] Hugs98-plus-Sept2006
by dfeustel＠mindspring.com 10 Dec '06

10 Dec '06

> On Sat, Dec 09, 2006 at 05:23:34PM -0600, Mark Hills wrote: > > [patient explanation of how Hugs finds hierarchical modules] > > > > I only have two files named Prelude.hs, the one under base and the one > > under hugsbase. The one under base simply wraps the one under hugsbase > > (it imports it at the end), I'm assuming to allow the definitions to be > > Hugs-specific (since they use primitives) while still providing a > > standard location for the Prelude, in case you want to run your programs > > using a different Haskell system like GHC. > > Another reason for a separate Hugs.Prelude is that it exports some > extra things. This is because Haskell 98 has the Prelude and some > other library modules import each other, and Hugs does not support > mutually recursive modules, I ran into the mutual recursion error when I attempted to load the GS.hs provided for _The Haskell Road..._. The term generating the error was 'case' although there was no instance of that word in GS.hs. I still have a lot to learn about how Hugs works. Dave > so it simulates it by having the Prelude > and the other modules import another module with the real definitions > (Hugs.Prelude). Also, Prelude.hs is shared code with GHC, except for > the imports (courtesy of cpp).

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Re: [Hugs-users] Hugs98-plus-Sept2006
by dfeustel＠mindspring.com 10 Dec '06

10 Dec '06

> On Sat, Dec 09, 2006 at 11:11:21PM +0000, dfeustel(a)mindspring.com wrote: > > the 'find' command does not find a file by the name of Hugs.Prelude anywhere > > in the Hugs98 tree or in /usr/local/lib/hugs, nor in the default path, as far > > as I can tell. There are, þowever, 5 different instances of Prelude.hs in the > > Hugs98 tree. Why is there more than 1 instance of Prelude.hs (with different > > contents to boot) in Hugs98 source? > > % find /usr/local/lib/hugs -name Prelude.hs | xargs grep ^module > /usr/local/lib/hugs/packages/hugsbase/Hugs/Prelude.hs:module Hugs.Prelude ( > /usr/local/lib/hugs/packages/base/Prelude.hs:module Prelude ( > > They are different modules, with the second (the Prelude, as defined > in Haskell 98) importing the first (Hugs.Prelude, the internal Hugs > implementation). The search path contains /usr/local/lib/hugs/packages/*, > so when asked to load module A.B.C, Hugs looks for As I read more of the Hugs documentation, I am getting the impression that the documentation terms are changing to reflect a change in the software organization. > > (section 2.2 of the Hugs User's Guide) The point is that if the file > thus found does not describe itself as module A.B.C, the load will fail. > Now plug Hugs.Prelude and Prelude into the above, and we get the behaviour > you are seeing. The problem is that you have a file Prelude.hs in your > search path that does not start with "module Prelude". The Prelude.hs in my $HOME is a copy of the Prelude.hs in packages/hugsbase/Hugs/Prelude.hs - the 65355 char version. (Note the difference in file sizes. It looks like the small Prelude.hs is just the Hugs.Prelude module.) find . -name Prelude.hs -ls 65355 Dec 8 18:51 ./packages/hugsbase/Hugs/Prelude.hs 4100 Dec 8 18:51 ./packages/base/Prelude.hs Dave

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Re: [Hugs-users] Hugs98-plus-Sept2006
by dfeustel＠mindspring.com 09 Dec '06

09 Dec '06

> On Sat, Dec 09, 2006 at 09:38:37PM +0000, dfeustel(a)mindspring.com wrote: > > What I have discovered is that þugs, invoked with no arguments, > > initializes itself differently depending upon the presence or absence > > of Prelude.hs in the $HOME directory. With Prelude.hs *not* present > > in $HOME, I get the behavior described in the original post. When > > Prelude.hs *is* present in $HOME, then an error re loading Prelude.hs > > is reported, and primMinInt/primMaxInt/primMaxChar all work and the > > prompt is 'Hugs.Prelude>'. > > You have a file called Prelude.hs containing a module Hugs.Prelude in > your current directory. When Hugs starts, it loads Hugs.Prelude, which > it finds in the default path, the 'find' command does not find a file by the name of Hugs.Prelude anywhere in the Hugs98 tree or in /usr/local/lib/hugs, nor in the default path, as far as I can tell. There are, þowever, 5 different instances of Prelude.hs in the Hugs98 tree. Why is there more than 1 instance of Prelude.hs (with different contents to boot) in Hugs98 source? > and then attempts to load Prelude from > Prelude.hs (because . is at the front of the search path). However this > file contains a module Hugs.Prelude, not the Prelude it was expecting, > and initialization fails. Initialization does not fail. Hug terminates when initialization fails. Initialization takes a different path when it encounters Prelude.hs in either $HOME or . directories. The alternate initialization path makes hug work as the Haskell book describes on page 13. Where is the module Hugs.Prelude found during hugs initialization, if not in Prelude.hs? > The error message when Hugs finds a file to contain the wrong module > could be better, though. I agree. Perhaps some standardization of terminology would help too. Dave

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Re: [Hugs-users] Hugs98-plus-Sept2006
by Mark Hills 09 Dec '06

09 Dec '06

> Module names are built reflecting the directory structure, with separate > starting directories for different products. If you start Hugs and type > :set, you will see something like this for the search path: > > Search path : > -P.:{Home}/lib/hugs/packages/*:/usr/local/lib/hugs/packages/*:{Hugs}/packages/* > > So, each directory under lib/hugs/packages is added to the path, > including (for instance) base and hugsbase. The hugsbase directory > contains a Hugs directory, which contains a Prelude.hs file. Looking at > the file, you will see that it says it defines module Hugs.Prelude, > which makes sense since the file name is Hugs/Prelude.hs. Similarly with > Data.Map, which is under the base directory in file Data/Map.hs. > > I only have two files named Prelude.hs, the one under base and the one > under hugsbase. Same for me in /usr. I definitely got confused by the multiple instances of Prelude.hs in /usr and in Hugs98 source. I'm recovering. Thanks for the additional info (below). Dave > The one under base simply wraps the one under hugsbase > (it imports it at the end), I'm assuming to allow the definitions to be > Hugs-specific (since they use primitives) while still providing a > standard location for the Prelude, in case you want to run your programs > using a different Haskell system like GHC. > > Mark > > dfeustel(a)mindspring.com wrote: > >> On Sat, Dec 09, 2006 at 09:38:37PM +0000, dfeustel(a)mindspring.com wrote: > >> > >>> What I have discovered is that þugs, invoked with no arguments, > >>> initializes itself differently depending upon the presence or absence > >>> of Prelude.hs in the $HOME directory. With Prelude.hs *not* present > >>> in $HOME, I get the behavior described in the original post. When > >>> Prelude.hs *is* present in $HOME, then an error re loading Prelude.hs > >>> is reported, and primMinInt/primMaxInt/primMaxChar all work and the > >>> prompt is 'Hugs.Prelude>'. > >>> > >> You have a file called Prelude.hs containing a module Hugs.Prelude in > >> your current directory. When Hugs starts, it loads Hugs.Prelude, which > >> it finds in the default path, > >> > > > > the 'find' command does not find a file by the name of Hugs.Prelude anywhere > > in the Hugs98 tree or in /usr/local/lib/hugs, nor in the default path, as far > > as I can tell. There are, þowever, 5 different instances of Prelude.hs in the > > Hugs98 tree. Why is there more than 1 instance of Prelude.hs (with different > > contents to boot) in Hugs98 source? > > > > > >> and then attempts to load Prelude from > >> Prelude.hs (because . is at the front of the search path). However this > >> file contains a module Hugs.Prelude, not the Prelude it was expecting, > >> and initialization fails. > >> > > > > Initialization does not fail. Hug terminates when initialization fails. > > Initialization takes a different path when it encounters Prelude.hs in > > either $HOME or . directories. The alternate initialization path makes hug > > work as the Haskell book describes on page 13. Where is the module Hugs.Prelude > > found during hugs initialization, if not in Prelude.hs? > > > > > >> The error message when Hugs finds a file to contain the wrong module > >> could be better, though. > >> > > > > I agree. Perhaps some standardization of terminology would help too. > > > > Dave > > _______________________________________________ > > Hugs-Users mailing list > > Hugs-Users(a)haskell.org > > http://www.haskell.org/mailman/listinfo/hugs-users > >

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