Gpc April 1997

gpc@gnu.de

24 participants
111 discussions

Files
by berend＠beard.nest.nl 01 Feb '02

01 Feb '02

* Moved (from: gpc) by Berend de Boer using timEd 1.10.b3+. Peter Gerwinski wrote in a message to Berend de Boer: PG> I tried to use Extended Pascal "binding" to assign a file PG> variable to an external -- existing -- file. I just copied PG> the "Assign" pro- cedure by Berend as published in PG> borland2ep.doc. It does not always work: I often get a PG> runtime error saying that the file did not exist. If you can repeat it, compile with another Extended Pascal compiler, for example Prospero's one. If that fails too, there is really something wrong with the code. But I suspect gpc. You're using which OS? Groetjes, Berend (-: fido: 2:281/527.23 email: berend(a)beard.nest.nl

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What is standard, and what isn't?
by Peter Gerwinski 01 May '97

01 May '97

Hello, perhaps somebody can help to clarify the following two questions: 1) Is the comparision with `=' or `<>' of structured variables okay in ISO Pascal? ISO 10206 6.8.3.5 only says that the types to be compared must be compatible. If not, this might be a reasonable extension (already offered by some compilers, *not* including Borland Pascal;). 2) In GPC strings, the schema discriminant "Capacity" is accessible as a "record field" of the string. Is this okay by ISO 10206, and should it be done for other schemata this way, too? And how to tread the "length" field of a string? ISO 10206 6.4.3.3 does not say anything about that. I could imagine the string schema type to be something similar to Type String ( Capacity: Integer ) = record length: Integer; String: packed array [ 1..Capacity ] of Char; end (* String *); except that the "String" field is automatically dereferenced. Thanks for your help, Peter Dipl.-Phys. Peter Gerwinski, Essen, Germany, free physicist and programmer peter.gerwinski(a)uni-essen.de - http://home.pages.de/~peter.gerwinski/ [970201] maintainer GNU Pascal [970420] - http://home.pages.de/~gnu-pascal/ [970125]

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exit; ????
by skye 01 May '97

01 May '97

Is Exit not included in GPC? i.e. program test; procedure t1(a:integer); begin writeln('hello1'); if a = 1 then exit; writeln('hello2'); end; begin writeln('hello'); t1(1); t1(0); writeln('hello3'); end. should produce: hello hello1 hello1 hello2 hello3 but I get Undefined Indentifier 'Exit' I tried using return; and that works. I posted this question to the comp.lang.pascal NG and had someone from Borland tell me that Exit should do the trick (I didn't say I wasn't using TP tho). Is exit a Borland thing? -SC

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Re^3: Legal Change in GPC ?
by Peter Gerwinski 30 Apr '97

30 Apr '97

According to Christian Wendt: > :-) I do the work and get common to the RTS C source (which is very vell > readable!) - and then learn all the work has been done... Oh - sorry! Since an improved BPcompat package for DOS (DJGPP) will be released soon, what about facing Linux instead? Sven's BGI2GRX (Graph) Unit runs under Linux, but we have no CRT yet ... > PG>available in the `contrib' subdirectory of the GPC distribution. > BPCompat.pas is in my contrib subdirectory... but only "highlevel" > functions... The same stuff as in Borland's CRT, isn't it? > not "impossible"- you only got to reinvent the wheel and write to > $b80000... _big_ loss in portability & comfort (no easy to call writeln. Nevertheless this will remain my preferred method in BO5. The fastest thing you can imagine on the DOS platform. > BTW - is there a way to make a procedure to have a variable count of > parameters? (as writeln) - e.g. would it be possible to define to "C" > printf procedure within pascal ?) Yes and no: You can define a "Procedure Foo ( a, b: Integer; ... );" with a triple dot indicating a variable number of subsequent arguments, but I have not yet found out how to access them ... > But i think that even there it would be quite more comfortable to use > Textcolor instead of write(chr(27)+'[5;33m'); or such... Of course. But a CRT Unit could use these sequences to access the terminal in a portable way. > exactly what I had in mind... don't kill it from the alphas :-) Don't worry. If things develop as I hope, we will enter beta stage soon ... Greetings, Peter Dipl.-Phys. Peter Gerwinski, Essen, Germany, free physicist and programmer peter.gerwinski(a)uni-essen.de - http://home.pages.de/~peter.gerwinski/ [970201] maintainer GNU Pascal [970420] - http://home.pages.de/~gnu-pascal/ [970125]

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problem with gpclib.a (alpha-version)...
by A.ECKLEDER＠CHATEAU.cl.sub.de 30 Apr '97

30 Apr '97

A.Eckleder(a)chateau.cl.sub.de / oh no,some e-mail ... by ME!!! To: GPC(a)HUT.FI (Gpc) ---------------------------------------------------------------------- ...i've got some problem with the library file of the actual (?!?) alphaversion of gnu-pascal... obviousely there's some problem in string-management (gpc2.0 libs do well) here's some sample code: type normstr=string[255]; {also tested with different string lengths} function strng(z:real):normStr; {convert number to string} var s:normstr; k:byte; neg:boolean; begin k:=0; while (z<>int(z)) and (k<5) do begin z:=z*10; inc (k); end; s:='';if z<0 then neg:=true else neg:=false; z:=int(abs(z)); if z=0 then s:='0'; while z>0 do begin s:=chr(trunc(z-int(z/10)*10)+48)+s; z:=int(z/10); end; if k>0 then s:=copy(s,1,length(s)-k)+'.'+copy(s,length(s)-k+1,k); if neg then s:='-'+s; strng:=s; end; as far as i could analyse the problem,the error occurs within the s:=chr(trunc(z-int(z/10)*10)+48)+s; expression. i know that this is not very optimized code,but it normally works fine though. the other problem i realized with this alpha-version is that i couldn't manage to use the inline assembler. i only only got a message telling me function asm() not beeing existent. because of this strong behavior i use the gpc2.0 compiler with the alpha- libraries...perhaps THIS is the reason why the function above doesn't work, but i am not quite sure about that... andy /------------------- A.ECKLEDER(a)CHATEAU.CL.SUB.DE --------------------\ Who is 'General Failure' - And why is he reading my harddisk ? \------------------ Andreas Eckleder@2:2480/816.32 -------------------/ ## CrossPoint v3.1 ##

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Re: What is standard, and what isn't?
by Berend de Boer 30 Apr '97

30 Apr '97

Peter Gerwinski wrote: >Not too difficult: Integer arrays can be treated by a simple byte >compare; for string arrays the compiler must generate a loop. I thought that was a lot of work, but it seems I was wrong :-) >> Certainly: see the examples in 6.8.4 > >Thanks a lot! I didn't find that. Why wasn't there a single word >about >this in 6.4.7, 6.4.8??? No idea. Just like a lot of other topics treatment is fairly sparse. We need to have everything in one place. Maybe I should write an Extended Pascal programmers book :-) >What about the following: > > * Default mode (and Extended Pascal mode): The length field cannot > be accessed (except with "length ( MyStr )".) > > * With extended syntax (*$X+*): The length field can be read- and > write-accessed. I don't care, because I don't see the need for accessing the length field directory, as long as it is not available in Extended Pascal mode :-) Groetjes, Berend.

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Re: Short strings (Was: Modifying string length?)
by Peter Gerwinski 30 Apr '97

30 Apr '97

According to Stephen Lindholm: > [`ShortStr' or `ShortString'?] > How about supporting both? Since PEP and Delphi agree that this is called `ShortString', I conclude that we should use that, too. However it will take some time until it will be implemented: All string types must be compatible with each other in assignments, comparisions, etc., and all string routines will have to accept all sorts of strings. (Well ... at least some of them will accept all sorts; others might be okay to support EP's long strings only.) Peter Dipl.-Phys. Peter Gerwinski, Essen, Germany, free physicist and programmer Reply e-mail to "uni-essen" http://home.pages.de/~peter.gerwinski/ [970201] instead of "NO-SPAM-PLEASE". maintainer GNU Pascal [970412] kampi.hut.fi/gpc Sorry for the inconvenience. http://home.pages.de/~gnu-pascal/ [970125]

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Re: What is standard, and what isn't?
by Peter Gerwinski 30 Apr '97

30 Apr '97

According to Berend de Boer: > If you want something 'difficult' to do , implement integer and string > value arrays :-) Not too difficult: Integer arrays can be treated by a simple byte compare; for string arrays the compiler must generate a loop. This can be done for records, too: The compiler can do a loop through the fields of the record. (User programs cannot do that. :-P) > Certainly: see the examples in 6.8.4 Thanks a lot! I didn't find that. Why wasn't there a single word about this in 6.4.7, 6.4.8??? > I think one implements it as: > > Type > String ( Capacity: Integer ) = record > length: Integer; > String: packed array [ 1..Capacity+SizeOf(Char) ] of Char; > end (* String *); It's "1..Capacity + 1". (Increasing the index by one adds one char.) (And it's still an exception since you write "MyStr [ i ]", not "MyStr.String [ i ]".) > However length is not specified in the standard, so it should not be > accessible with Extended Pascal. You can always use length(MyStr) to > achieve the same functionality. What about the following: * Default mode (and Extended Pascal mode): The length field cannot be accessed (except with "length ( MyStr )".) * With extended syntax (*$X+*): The length field can be read- and write-accessed. Okay like that? Or perhaps better to have it in default mode, too, and to switch it OFF in Extended Pascal mode? I think it's best as above because you should assign a new length to a string only if you know exactly what you are doing. Greetings, Peter Dipl.-Phys. Peter Gerwinski, Essen, Germany, free physicist and programmer peter.gerwinski(a)uni-essen.de - http://home.pages.de/~peter.gerwinski/ [970201] maintainer GNU Pascal [970420] - http://home.pages.de/~gnu-pascal/ [970125]

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Re: Modifying string length?
by Peter Gerwinski 30 Apr '97

30 Apr '97

According to Frank Heckenbach: > > Hmmm... well, I could not see the effect. I wrote the following test program: > [...] > I compiled it with "-O3 -S". The resulting code contained two calls to > _memcpy. [...] Ah - I was wrong, sorry. The string addition is optimized, but it is done on a temporary variable, and the assignment to that guy is *not* optimized. Maybe this can be changed ... I will have a look at that. (But not now.) (* By the way: Good news for all friends of schemata! They might be finished (except, of course, bugs) this week ... *) Greetings, Peter Dipl.-Phys. Peter Gerwinski, Essen, Germany, free physicist and programmer peter.gerwinski(a)uni-essen.de - http://home.pages.de/~peter.gerwinski/ [970201] maintainer GNU Pascal [970420] - http://home.pages.de/~gnu-pascal/ [970125]

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Re: Short strings (Was: Modifying string length?)
by The African Chief 30 Apr '97

30 Apr '97

On Wed, 30 Apr 1997 00:41:07 +0200 (MET DST) Peter Gerwinski <peter(a)agnes.dida.physik.uni-essen.de> wrote: >According to The African Chief: >> According to Frank Heckenbach: >> >255 chars max length are sometimes not enough. >> But you can use normal GPC strings for that. > >Just my point: For applications where you need looooong strings, GPC's ><=2GB strings with 8 bytes of overhead are perfect. In those cases >where you must save space, 255 characters are fine - and they are >compatible to UCSD and Borland Pascal. > >Should it be `ShortString' or `ShortStr'? In analogy to `LongInt' >instead of `LongInteger' I would vote for `ShortStr'; OTOH, Prospero's >Extended Pascal compiler (PEP) has `ShortString' for this ... Delphi also has "ShortString" - so perhaps we should use that. Best regards, The Chief Dr Abimbola A. Olowofoyeku (The African Chief, and the Great Elephant) Author of: Chief's Installer Pro v3.12 for Win16 and Win32. Homepage: http://ourworld.compuserve.com/homepages/African_Chief/ E-mail: laa12(a)cc.keele.ac.uk

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Gpc April 1997