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Re: curses suggestions wanted
by Peter Gerwinski 06 Aug '97

06 Aug '97

According to Ken Linder: > > While working on a curses (ncurses) interface I have come upon a situation > whereby I need some directions from potential GPC ncurses users. Certain > ncurses functions require a PCHAR pointing to a string for the function to > use. Would you, the potential users, rather pass a string schema instead? Yes, but this is no real problem (see below). > Personaly I would like an ncurses lib where I only pass strings when I can. > > Any ideas or suggestions? > > I could also allow either type of call... > > C style: > addstr(PChar); > > GPC style > gaddstr(String); In such situations, where the procedure/function does not change the parameter, you can declare it with a `PChar' parameter. GPC knows what to do if the user passes a String schema and implicitly passes the address of the string data instead of the address of the schema. OTOH if the String is in fact a `Var' parameter (I don't know if such functions exist in [n]curses), you must decide whether this shall be a `PChar' or a String schema. In such cases I would prefer to have the `String' variant as the default and the `PChar' variant as an extensions, i.e. C style: Procedure cfoo ( Var S: pChar ); GPC style: Procedure foo ( Var S: String ); (* NB: You needn't specify the length of the string in `Var' parameters, but you must do so for the return value of a function. *) 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 [970714] - http://home.pages.de/~gnu-pascal/ [970125]

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Some patches
by Peter Gerwinski 06 Aug '97

06 Aug '97

Hello, everybody! I uploaded four patches from gpc-970714 to the "current state of the art", gpc-970806, to ftp://agnes.dida.physik.uni-essen.de/gnu-pascal/beta. A detailed list of changes will follow with the next beta release. While there are only minor changes (bug fixes) to GPC, I started to make up the documentation crucially; comments are welcome. 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 [970714] - http://home.pages.de/~gnu-pascal/ [970125]

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curses suggestions wanted
by Ken Linder (KC7RAD) 06 Aug '97

06 Aug '97

Hi all, While working on a curses (ncurses) interface I have come upon a situation whereby I need some directions from potential GPC ncurses users. Certain ncurses functions require a PCHAR pointing to a string for the function to use. Would you, the potential users, rather pass a string schema instead? Personaly I would like an ncurses lib where I only pass strings when I can. Any ideas or suggestions? I could also allow either type of call... C style: addstr(PChar); GPC style gaddstr(String); Later... Ken L.

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attribute(section(".ltext)) segfault
by Bill Currie 06 Aug '97

06 Aug '97

:) Why's it always me that finds the seg-faults? :) The test on line 534 of gpc-common.c segfaults due to `args' (?) not being what's expected. I had a look at the attribute handling in parse.y, but couldn't figure it out myself, so I've attached an offending file. Also, how the heck do I get attribute() to work with variables? I keep getting parse errors or other wierdnesses. Bill -- Leave others their otherness. The following section of this message contains a file attachment prepared for transmission using the Internet MIME message format. If you are using Pegasus Mail, or any another MIME-compliant system, you should be able to save it or view it from within your mailer. If you cannot, please ask your system administrator for assistance. ---- File information ----------- File: foo.pas Date: 6 Aug 1997, 17:20 Size: 111 bytes. Type: Program-source

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bison and flex with GPC
by Peter Gerwinski 05 Aug '97

05 Aug '97

According to Tom Dye: > > Please excuse a newbie request for help. I'm interested in using a lexer > prepared with flex in a GPC program. I gather from the documentation that > this is possible, but I'm not enough of a C programmer to figure out how > it might be done. This is a special case of the question "How to use a function written in C from a GPC program?", correct? This is answered in the GPC FAQ: 8< ---- begin (* from the GPC FAQ *) ----------------------------------------- [15]How do I use <insert_your_function_here> from the C library? GNU Pascal can use every function of your C library, but it may be up to you to write declaration of an external function, before you can use it. Consider the function `sleep'. `man(3) sleep' reveals: --------------------------------------------------------- NAME sleep - Sleep for the specified number of seconds SYNOPSIS #include <unistd.h> unsigned int sleep(unsigned int seconds); --------------------------------------------------------- This small demo program shows how to use `sleep' in a Pascal program: --------------------------------------------------------- program SleepDemo; type word = __unsigned__ integer; function sleep(seconds: word): word; C; var result : word; begin result := sleep(10); end. ---------------------------------------------------------- 8< ---- end (* from the GPC FAQ *) ------------------------------------------- Remark: Recent beta versions of GPC (available at ftp://agnes.dida.physik.uni-essen.de/~gnu-pascal/beta/) don't need `word = __unsigned__ integer' any more; they have `word' built in. Hope this helps, 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 [970714] - http://home.pages.de/~gnu-pascal/ [970125]

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bison and flex with GPC
by Tom Dye 05 Aug '97

05 Aug '97

Hello, Please excuse a newbie request for help. I'm interested in using a lexer prepared with flex in a GPC program. I gather from the documentation that this is possible, but I'm not enough of a C programmer to figure out how it might be done. Has anyone had experience with this? Can someone provide me with an example of how it might be done? Many thanks in advance. Tom Thomas S. Dye, Ph.D. Home: 813 16th Avenue, Honolulu, Hawaii 96816. Voice (808) 734-2087. Work: International Archaeological Research Institute, Inc., 949 McCully St., Suite 5, Honolulu, Hawaii 96826. Voice (808) 946-2548; Fax 943-0716.

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Re: gpi-hash.c segfaults
by Peter Gerwinski 04 Aug '97

04 Aug '97

According to Bill Currie: > On 31 Jul 97 at 15:08, Jukka Virtanen wrote: > > I suggest that this problem is fixed by casting > > the result of the pointer subtraction to > > (unsigned ptrdiff_t) which is always large enough, > > something like: > > One slight problem: I couldn't find a `ptrdiff_t' in djgpp. However, > it could always be created. Not a slight, but a big problem: (i) See `../cccp.c', line 51; (ii) `ptrdiff_t', even if it exists, is a signed type, and GCC doesn't accept `unsigned ptrdiff_t'. :-( To work around, what about the following? It only must produce a more-or-less unique number ... /* We must avoid negative values. Naturally, we would cast this to * `unsigned ptrdiff_t', but since we cannot be sure that the platform * we compile GPC on will support this, we use `abs' instead. */ #define HASH_FUNC(NODE) ((abs ((NODE) - (tree) 0) >> 2) % MAX_HASH_TABLE) 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 [970714] - http://home.pages.de/~gnu-pascal/ [970125]

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Pending bugs?
by Peter Gerwinski 04 Aug '97

04 Aug '97

Hi! I have only one thing to fix up before the next beta: The run-time system must learn how to read/write `LongInt's and such. `write[ln]' already works. (Thanks, Frank!) Anything else? Bernhard, did you succeed to reproduce that OOP-related bug? 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 [970714] - http://home.pages.de/~gnu-pascal/ [970125]

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Re: GetFile builtin function
by Peter Gerwinski 04 Aug '97

04 Aug '97

Hi, Bill! Hi, everybody! According to Bill Currie: > > Isn't. That is: the function is provided in rts-file.c (_p_getfile), > but it's not supported by the compiler. You can write `Function GetFile: Pointer; AsmName `_p_getfile';' into your program and just use it, but I see, you want more than this. :-) > How do I go about adding > this (or others) function? I'ld rather get instructions on how to do > it myself rather than a patch (though I can study the patch) so I can > learn how do to it to add more functions later on (such as Lo, Hi > etc). That would be great! Here is a recipe how to introduce a new built-in function into GPC. If it looks like French for you, feel free to ask me - I can speak French (more or less). * Edit `util.c', go into the `KItable[]' and add this identifier with the appropriate flags (`GNU_PASCAL' since it is not part of any other standard). (Perhaps after `DefineSize' is a nice place?) (First Letter Capitalized.) * Edit `parse.y' and add `gpc_GETFILE' (my suggested name for it) to the list of tokens (= constant definitions), perhaps after `p_DEFINESIZE'. * In `parse.y', look how something similar is implemented (e.g., again, `p_DEFINESIZE') and do it similarly. This means: - Give it a return type: "%type <ttype> gpc_GETFILE". - Add it to `new_identifier_1', so the name remains redefinable. - Add it to `rts_fun_onepar', so the parser will take it into account. In case you are not familiar with Bison (I was not when I found GPC): This language essentially is a machine-readable form of syntax diagrams. The `bison' program translates this into a C file not intened to be read by humans. The C stuff indented with two tabs is the "action" to be taken if the pascal parser reads this syntax. * Again in `util.c', function `build_rts_call', write a handler for `gpc_GETFILE'. This is where the real work is done; all the above is administrative stuff. But in this case, it's quite simple: Do the same as `case p_DEFINESIZE' does, i.e. warn about ISO violation, check for errors (hmm ... these functions don't count their arguments ... looks like a bug in GPC ... we should check it ...), and pass the argument to the other parts of `build_rts_call' which will do the work. * Don't forget to follow the GNU coding style guidelines. * Don't forget to send me a patch, so I can study it. ;-) * What about doing the same for `ParamCount' and `ParamStr'? The RTL functions do *almost* the same as their BP equivalents do. Perhaps we should make them truly compatible and built-in? (One problem: `ParamStr' must return a String of unknown length. Where to allocate it?) Welcome to the GNU Pascal development team! Yours, 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 [970714] - http://home.pages.de/~gnu-pascal/ [970125]

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GetFile builtin function
by Bill Currie 03 Aug '97

03 Aug '97

Isn't. That is: the function is provided in rts-file.c (_p_getfile), but it's not supported by the compiler. How do I go about adding this (or others) function? I'ld rather get instructions on how to do it myself rather than a patch (though I can study the patch) so I can learn how do to it to add more functions later on (such as Lo, Hi etc). TIA Bill -- Leave others their otherness.

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