Gpc October 2002

gpc@gnu.de

16 participants
17 discussions

Re: Conformant array curiosity
by Wood David 24 Mar '03

24 Mar '03

Frank, Thanks for your reply. I've managed to cut down the module to this very short module so I just get two errors, both - prior parameter's size depends on 'A': MODULE Test interface; export Test=(Test_proc); PROCEDURE Test_proc(List : ARRAY[a..b :INTEGER] OF DOUBLE); END. MODULE Test implementation; PROCEDURE Test_proc; BEGIN List[a]:= 2.3; List[2]:= 2.3; END; { Test_proc } END. The errors correspond to each assignment although the error line is the declaration. Sure enough, converting this to a unit fixes the problem: UNIT Test; Interface PROCEDURE Test_proc(List : ARRAY[a..b :INTEGER] OF DOUBLE); Implementation PROCEDURE Test_proc; BEGIN List[a]:= 2.3; List[2]:= 2.3; END; { Test_proc } END. Is the module syntax illegal or is it a bug? If it is a bug, at least you can take comfort in knowing it can kill the DEC Pascal compiler too! Regards David Wood, QinetiQ Farnborough The Information contained in this E-Mail and any subsequent correspondence is private and is intended solely for the intended recipient(s). For those other than the recipient any disclosure, copying, distribution, or any action taken or omitted to be taken in reliance on such information is prohibited and may be unlawful.

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BUG? empty else
by Eike Lange 08 Nov '02

08 Nov '02

Hi Folks! The following program compiles without warnings: { 2.1 (20020510), based on gcc-2.95.2 19991024 (release) } program bug; var i: Integer = 1; begin if i = 1 then WriteLn ('is 1') else if i = 2 then { do nothing } else { do nothing } end. Eike

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Re: BUG? empty else
by da Silva, Joe 01 Nov '02

01 Nov '02

Agreed. This is not a bug. This reminds me of the "case" statement in Pascal 6000 (CDC). If you wanted to prevent a crash of your program, when an expression (variant-selector) was not matched by any case-constant-list, you HAD TO include an empty "otherwise" clause. BTW, when I reported this behaviour (ie. crash) as a bug, I was told that since a non-match was undefined, it was acceptable for the program to terminate with a run-time error (which is what it normally did). Joe. > -----Original Message----- > From: CBFalconer [SMTP:cbfalconer@yahoo.com] > Sent: Friday, November 01, 2002 2:35 AM > To: gpc(a)gnu.de > Subject: Re: BUG? empty else > > Eike Lange wrote: > > > > The following program compiles without warnings: > > > > { 2.1 (20020510), based on gcc-2.95.2 19991024 (release) } > > program bug; > > > > var > > i: Integer = 1; > > > > begin > > if i = 1 then > > WriteLn ('is 1') > > else if i = 2 then > > { do nothing } > > else > > { do nothing } > > end. > > Not a bug. Terrible program structure, leading to much confusion, > but valid. The null statement is specifically permitted. You > will often see such things as: > > WHILE whatever DO (* nothing *); > > With if/else if/else chains, a useful rule is to put the short > clauses first (if possible) and make the final else the longest > clause. i.e.: > > IF something THEN BEGIN > (* lots of code *) > END > ELSE BEGIN > (* a few lines *) > END; > > is inferior to: > > IF NOT something THEN BEGIN > (* a few lines *) > END > ELSE BEGIN > (* lots of code *) > END; > > for readability reasons. You can look up from any code and find > the controlling statement easily. This applies to most > languages. The compiler should normally be able to optimize away > any extra code generated. > > -- > Chuck F (cbfalconer(a)yahoo.com) (cbfalconer(a)worldnet.att.net) > Available for consulting/temporary embedded and systems. > <http://cbfalconer.home.att.net> USE worldnet address! > >

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Archive moved
by Frank Heckenbach 29 Oct '02

29 Oct '02

The archive of this list has moved to http://gnu-pascal.de/crystal/gpc/en/ Frank -- Frank Heckenbach, frank(a)g-n-u.de, http://fjf.gnu.de/, 7977168E GPC To-Do list, latest features, fixed bugs: http://www.gnu-pascal.de/todo.html GPC download signing key: 51FF C1F0 1A77 C6C2 4482 4DDC 117A 9773 7F88 1707

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Debugging Pascal-code...
by Preben Mikael Bohn 29 Oct '02

29 Oct '02

Hi all... I am now trying to debug my code... However I have a problem with gdb... I have the following code: program hello; var testingint : integer; str : string; begin testingint := 432; str := 'Hello... '; writeln(str, testingint); end. I compile it with gpc -g -O0 --automake hello.pas --executable-file-name And run gdb with "gdb hello" I set a breakpoint at the start using "b hello.pas:6" and run it with "r". It stops fine, and when I have executed the next line (using "n") I try to print testingint using "print Testingint". But here I simply get "$1 = void"... What am I doing wrong here??? It prints out Str nicely (as a _p_schema-type, but I can live with that)... Best regards Preben ===== Computers are like airconditioners: They stop working properly if you open windows. __________________________________________________ Do you Yahoo!? HotJobs - Search new jobs daily now http://hotjobs.yahoo.com/

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Bug in GPC?
by Preben Mikael Bohn 28 Oct '02

28 Oct '02

Hi all, I have a *really* strage problem. In my main program I have the following code snippet: ... if ((currentEpoch <= endDate) and (currentEpoch >= startDate)) then begin err := computeResiduals( corrections, filters, gsObs, observationIndices, gsPos, gpsPos, currentEpoch, residuals, estimatedClocks, errorSats); ... This works fine. If I add a writeln such as this: ... if ((currentEpoch <= endDate) and (currentEpoch >= startDate)) then begin writeln('xxx'); err := computeResiduals( corrections, filters, gsObs, observationIndices, gsPos, gpsPos, currentEpoch, residuals, estimatedClocks, errorSats); ... then my function "computeResidual" suddenly fails????? What is going on? Does anyone have an idea? It should be noted that "computeResidual" does not read from stdin or anything... My gpc runs on linux ans is version 2.1 (20020510) based on gcc-2.95.2 19991024 (release). Best regards Preben __________________________________________________ Do you Yahoo!? Y! Web Hosting - Let the expert host your web site http://webhosting.yahoo.com/

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Conformant array curiosity
by Wood David 25 Oct '02

25 Oct '02

Hi, I've been using conformant arrays in procedure declarations for ages, but recently I was given a troublesome module which had a number of procedure declarations, each with conformant parameters. When compiling the exported procedure, it actually caused our DEC Pascal compiler to crash (the stack dump suggesting it was whilst trying to build a conformant expression). Trying our faithful gpc 2.1 compiler, I got about 50 polite error messages "prior parameter's size depends on xyz" where xyz is a conformant array bound. However I can't figure out what has triggered this error. Can anyone shed any more light on how this may occur? Regards David Wood QinetiQ, Farnborough The Information contained in this E-Mail and any subsequent correspondence is private and is intended solely for the intended recipient(s). For those other than the recipient any disclosure, copying, distribution, or any action taken or omitted to be taken in reliance on such information is prohibited and may be unlawful.

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GPC on Darwin
by Adriaan van Os 22 Oct '02

22 Oct '02

As I am new on this discussion list, I have included some information about myself at the bottom of this message to introduce myself. My field of interest is GPC for Darwin (Darwin is Apple’s open-source kernel of MacOS X, based of FreeBSD 4.4 UNIX). I gathered the following relevant information: - the first version of GCC that fully supports Darwin is GCC 3.1 - GPC 2.1 is based on GCC 2.95 - GPC-20020910 alpha/beta has patches (diffs) for GCC 3.0 Consequently, my questions are: - has anyone on this list tried to build GPC for Darwin ? - has anyone on this list tried to build GPC for GCC 3.1 ? Regards, Adriaan van Os gpc(a)microbizz.nl --------------------------------------- About myself I run a small software company in The Netherlands named Microbizz. You are invited to laugh about my website at www.microbizz.nl. Currently, I am working mainly on CAD software and application toolboxes. Pascal is my language of choice. I have worked with the following Pascal compilers: DEC-10 (1978) DEC-10 Pascal Apple II UCSD Pascal Apple IIgs TML Pascal ORCA Pascal CPM Turbo Pascal 1.0 MS-DOS Turbo Pascal 3.0 upto 6.0 Windows Delphi Macintosh Turbo Pascal Think Pascal Apple Pascal for MPW Language Systems Pascal for MPW MetroWerks Pascal CodeWarrior Pascal Darwin See forward to work with GPC. What I most liked about what I learned from GPC was it’s ability to pass local procedures as actual parameters !!

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procedure parameter defaults
by Nick Ioffe 22 Oct '02

22 Oct '02

Hi! In ADA and Vax Pascal there is a way of specifying default parameters: procedure a (x : integer := 10; y : string := 'abcdefg'); and to call a with specific argument: Var var1 : integer; var2 : string; Begin var1 := 5; var2 := 'hello'; a ( x := var1); a; a ( y := var2); a (var1, var2); 2 questions: 1. is there any way of doing so in GPC 2. if answer to #1 is "no" is it possible to include it in todo list Thank you in advance, Nick

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Wishlist: asmname for constants
by Eike Lange 20 Oct '02

20 Oct '02

Hi Folks! Porting a library to a GNU Pascal Unit sometimes means putting a variable instead of a constant. Like this: foo.c: --------- int _c_konstant = DEFINED_CONSTANT_IN_C; --------- foo.pas: ----------- unit Foo; interface {!! Treat them as constant !!} var Konstant: Integer; asmname '_c_konstant'; external; implementation {$L foo.c} end. ----------- Doing it this way means a lack of using these "constants" in a "case" statement. It would be nice to have a feature like: const Konstant = _c_konstant; or similar. -- Eike Lange

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Gpc October 2002