Gpc January 2001

gpc@gnu.de

25 participants
28 discussions

bug in gpc-20010101
by Maurice Lombardi 08 Jan '01

08 Jan '01

Hello I have compiled this snapshot with djgpp (W98 dos box). Seems successfull but the crtdemo.pas, as well as other programs of mine which use crt, fail. To check that nothing has gone wrong with my djgpp setup I have then compiled some previous snapshots. Everything seems correct up to 20001230 (which succeeds with crtdemo and the whole test suite). 20001231 fails to compile with a message: make.exe[2]: *** No rule to make target `/djgpp/gnu/gcc-2.952/gcc/p/../ggc-callbacks.c', needed by `ggc-callbacks.o'. Stop. looks like a mistyping... It seems to have been corrected in 20010101 which compiles OK, but something else is hidden. Since djgpp and linux you mainly use are different with respect to crt and curses it may have been unnoticed in your setup. Hope this helps Maurice -- Maurice Lombardi Laboratoire de Spectrometrie Physique, Universite Joseph Fourier de Grenoble, BP87 38402 Saint Martin d'Heres Cedex FRANCE Tel: 33 (0)4 76 51 47 51 Fax: 33 (0)4 76 51 45 44 mailto:Maurice.Lombardi@ujf-grenoble.fr

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Re: Conditional expressions
by Tom Verhoeff 05 Jan '01

05 Jan '01

Frank wrote: >Tom Verhoeff wrote: > >> >Peter and I are discussing the possibility of including some kind of >> >conditional operator, like `foo ? bar : baz' in C. Since GPC uses >> >GCC's backend, this should be easy to do semantically, the main >> >question is about syntax: >> >> I would like to propose the following syntax: >> >> <expr> if <cond> else <expr> >> >> This is concise and nice (you can view "if <cond> else" as infix operator). >> Disadvantage: it requires priorities/parentheses for proper binding, >> it uses the if/else, which also appears in the conditional statement >> (this is also an advantage, since it does not require new reserved >> words/symbols). > >This doesn't seem to cause parsing conflicts, AFAICS. However, it's >quite different from `if' statements (and therefore maybe >confusing), so I'd tend to favour the if-then-else version... Because it is quite different, it is LESS confusing. If it would be very similar to the way the conditional statement is expressed, then it could be confusing, because when you quickly read some code you wouldn't immediately see whether you are dealing with a large conditional expression or just a conditional statement. On the other hand, if you would only know that GPC supports conditional expressions, but you would not know the exact syntax, then most people would simply try the if-then-else version and not my proposed if-else. Therefore, the if-then-else seems preferable. Tom

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ARGV
by Oldham, Adam 04 Jan '01

04 Jan '01

Hello All, The Support page says you can risk support here so I will try. I am trying to port from an old SVS Pascal compiler under SCO Unix to Linux using GPC, and having a few problems and very little resources to find answers. In the main part of the program I am using this: InputDir := ARGV[2]^; when compiled using so special compiler parameters, I get this: editpars.pas:400: undeclared identifier `Argv' (first use this function) editpars.pas:400: (Each undeclared identifier is reported only once editpars.pas:400: for each function it appears in.) editpars.pas:400: subscripted object is not an array or string I am stumped and can't find any GPC references to using ARGV. Any ideas? Adam ----------------------------------------------------------------------- C. Adam Oldham Marconi Commerce Systems Inc. Software Engineer 7300 West Friendly Ave. adam.oldham(a)marconi.com Greensboro, NC 27420-2087 Phone : 336.547.5952 Fax : 336.547.5079 ----------------------------------------------------------------------- This document contains confidential information of Marconi Commerce Systems Inc. In consideration of the receipt of this document, the recipient agrees not to reproduce, copy, use or transmit this document and/or the information contained herein, in whole or in part, or to suffer such actions by others, for any purpose except with written permission, first obtained, of Marconi Commerce Systems Inc., and further agrees to surrender the same to Marconi Commerce Systems Inc. upon demand. -----------------------------------------------------------------------

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install GPC20001218 on rs6000 with AIX 4.3.2
by nicolas bley 04 Jan '01

04 Jan '01

We are currently using the GPC 2.0, but this version does not provide all the functions we need, especially concerning file handle. To solve these problems, we want to install a more recent GPC version on our RS6000. We intend to use: gcc : 2.95.2 gpc : 20001218 AIX : 4.3.2.0 We run the compile process as following: > ./configure --enable-languages=pascal > make LANGUAGES=pascal We get the following error: make[2]: Entering directory `/usr/local/src/gcc-2.95.2/gcc/p' rm -f ../gpc1 gcc -DIN_GCC -DGPC -g -O2 -DHAIFA `case "gcc" in *gcc*) echo -Wall;; esac` -o ../gpc1 \ `cat stamp-gbe` ../c-aux-info.o ../c-iterate.o ../c-pragma.o gpc-common.o gpc-convert.o gpc-decl.o lang.o gpc-lex.o gpc-typeck.o module.o gpi-hash.o circle-buf.o memfiles.o objects.o parse.o rts.o types.o util.o setop.o `if [ xobstack.o != x ]; then echo ../obstack.o; else true; fi` `case "gcc" in "cc") if [ xalloca.o != x ]; then echo ../alloca.o; else true; fi ;; esac` `if [ x != x ]; then echo ../; else true; fi` -lld ../../libiberty/libiberty.a collect2: ld returned 12 exit status ld : 0711-781 ERROR : TOC capacity overflow. TOC size : 69120. Maximum size : 65536 make[2]: *** [../gpc1] Error 1 make[2]: Leaving directory `/usr/local/src/gcc-2.95.2/gcc/p' make[1]: *** [gpc1] Error 2 make[1]: Leaving directory `/usr/local/src/gcc-2.95.2/gcc' make: *** [all-gcc] Error 2 Note : The LD message was written in french and we translated it in english. We found a way to correct it by modifying the GPC makefile line ALL_WARNINGS = `case "$(CC)" in *gcc*) echo -Wall ;; esac` in ALL_WARNINGS = `case "$(CC)" in *gcc*) echo -Wall -Wl,-bbigtoc;; esac` Is that correction necessary or can we solve the problem another way during the configuration stage? Note : We verified that the systems patches IX75823, IX87327 and IX87913 are installed and used on our AIX platform. After the correction, we still get a warning. The message is: ld : 0711-783 WARNING : TOC capacity overflow. Size : 69120. Maximum size : 65536 Creation of correcting instructions in process for each symbol capacity overflow make[2]: Leaving directory `/usr/local/src/gcc-2.95.2/gcc/p' Nevertheless compilation process goes on, up to other error: make[2]: Leaving directory `/usr/local/src/gcc-2.95.2/gcc' touch stmp-multilib gcc -DIN_GCC -DHAIFA -g -O2 -DHAVE_CONFIG_H -I. -I. -I./config -I./../include \ -DTARGET_MACHINE=\"powerpc-ibm-aix4.3.2.0\" -DUSE_COLLECT2 \ -c `echo ./collect2.c | sed 's,^\./,,'` In file included from collect2.c:98: /usr/include/ldfcn.h:47: #error -qlonglong must be used make[1]: *** [collect2.o] Error 1 make[1]: Leaving directory `/usr/local/src/gcc-2.95.2/gcc' make: *** [all-gcc] Error 2 Did someone already install that GPC version or any GPC version upper than 2.0 on AIX 4.3.2? What can we do to get a succesfull installation on this OS? Thank you for your help.

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Conditional expressions
by Frank Heckenbach 03 Jan '01

03 Jan '01

Hi! First of all: Happy New Millennium! :-) Peter and I are discussing the possibility of including some kind of conditional operator, like `foo ? bar : baz' in C. Since GPC uses GCC's backend, this should be easy to do semantically, the main question is about syntax: - ?: like in C -- the symbols wouldn't conflict AFAICS, but it seems to me quite un-Pascalish... - if foo then bar else baz (i.e., the same syntax as conditional statements, just with expressions, e.g. `x := if cond then 42 else 17'). Possible problems: * dangling else (probably not since each conditional operator will be required to have an else clause) * conflicts with `if' statements when nested into them (maybe not either for the same reason) * issues with precedence (compared to other operators) and associativity (i.e., how nested conditional operators will be interpreted) -- C has the same issues and resolves them with some rules, but like all such issues, they can confuse programmers sometimes (think of precedence of `and' and `or')... - if foo then bar else baz endif (or `fi' instead of `endif') -- this would avoid all the problems and make the syntax somewhat clearer I think... - if foo then bar else baz end -- the same, but without introducing a new reserved word (of which there are already way too many), and `end' is unambiguous in this context AFAICS. - Peter seems to remember that other Pascal compilers and related languages have something like this. Does someone know anything about these? Maybe we don't have to reinvent the wheel... - Other suggestions? Frank -- Frank Heckenbach, frank(a)g-n-u.de, http://fjf.gnu.de/ GPC To-Do list, latest features, fixed bugs: http://agnes.dida.physik.uni-essen.de/~gnu-pascal/todo.html

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Re: Conditional expressions
by j.logsdon＠lancaster.ac.uk 02 Jan '01

02 Jan '01

On Tue, 2 Jan 2001, Clive Rodgers wrote: > Maurice Lombardi a ecrit : > > Indeed, it was already in Algol60, the first ancestor of Pascal. > > The syntax was as above > > > > x := if cond then 42 else 17 > > > > and I had some trouble in beginning with Pascal to give away this very > > natural syntax ! > > > > No dangling else, use of () to be sure in case of doubt about precedences > > would be the simplest (but I have an historical bias !) > > > > Hope this helps > > > > Maurice > > > > As a native Algol60 speaker, I agree - this was one of the features I > too missed when Algol60 faded away. Syntax is close to natural > language (easy to teach, easy to learn, and a clean syntax - that is > the fundamental principle of Pascal). The rules of precedence for > Algol60 are basically evaluate from left to right unless specific > rules apply - isn't that already the case for Pascal? I don't think > we need anything else. The endif (or end) construction is un-Pascalish > - use parentheses if required, in the same way as begin/end is used > when needed for conditional statements. > As another ex-Algol60 (my first language on an Elliot 503, just to show my age!) this is quite natural but I am not sure that there is that much to recommend it since it would make the program much less portable to other Pascal environments. I think the gpc team should be careful not to go too far down a divergent route. After all, open standards are there for guidance and to avoid some of the more destructive activities of certain Large Companies and it would be a little hypocritical of open source advocates to follow this bad example. However, why restrict it to the RHS? ISTR that in Algol68 (or was it SCL, the ICL VME operating system language) you could say: if cond1 then a else b := if cond2 then expr1 else expr2 or something like that, which could lead for example to (I think in SCL) the following curious-looking statement (until you worked out what it was doing): if if then then else else := if not then while else for since there were no reserved words (the compiler being sufficiently clever to work out when to expect one!). Fun to read anyway! BTW while discussing other Algol/Pascal-like languages, does anyone know why in ADA95, there are no sets? This is a large omission I think. Happy New Millenium too to all of you - the numerate millenium. I noted from DW-TV the other day that there is one town in Germany that refused to celebrate last year and one country (Cuba) also. There is hope for us all! Best wishes John

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unit crt
by robi＠free.fr 02 Jan '01

02 Jan '01

Hello, I see in /usr/lib/gcc-lib/i386-linux/2-95-2/units/ the unit crt.pas, but if I write: uses crt in my program I get the message: module/unit interface 'crt' could not be imported. I read the FAQ on the subject but I did not find the solution. Thanks in advance for eventual help. Gerard.

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Re: Conditional expressions
by Tom Verhoeff 02 Jan '01

02 Jan '01

>Peter and I are discussing the possibility of including some kind of >conditional operator, like `foo ? bar : baz' in C. Since GPC uses >GCC's backend, this should be easy to do semantically, the main >question is about syntax: I would like to propose the following syntax: <expr> if <cond> else <expr> This is concise and nice (you can view "if <cond> else" as infix operator). Disadvantage: it requires priorities/parentheses for proper binding, it uses the if/else, which also appears in the conditional statement (this is also an advantage, since it does not require new reserved words/symbols). This syntax (not the sugar) is preferred by Tony (sir C.A.R.) Hoare in Unifying Theories of Programming C.A.R. Hoare and He Jifeng Prentice-Hall, 1998 Hoare uses sugar with a left-pointing open triangle instead of "if" and a right-pointing open triangle instead of else: ( Expr1 <| Cond |> Expr2 ) I do not think this is a very "urgent" extension (but it would have been nice if it had been taken up in some standard). Tom Verhoeff

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Gpc January 2001