Pike-devel September 2007

pike-devel@lists.lysator.liu.se

5 participants
9 discussions

Process.run
by Peter Bortas (nu med mindre Opera) ＠ Pike (-) developers forum 15 Jul '08

15 Jul '08

I just checked in a Process.run() in 7.7: http://pike.ida.liu.se/development/cvs/diff.xml?module=Pike&file=7.7/lib/mo… The rational for that is that I was once again reminded by a user this week that getting Process.create_process() or Process.Process right without some corner case blocking is hard. It's not obvious that if you bind pipes to booth stderr and stdout you have to take in to account that OS buffers are not limetless. Process.run() is a thin wrapper around Process.Process that collects stdout, stderr and exitcode and return them in a mapping. This could potentially result in huge strings, but will do what most users want and even already do when they call create_process() with both pipes bound. Something like this should be in 7.8, but I'm open to suggestions for other things that might be usefull to return in the mapping or for changing member names.

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Getopt mark II
by Martin Nilsson (Opera Mini - AFK!) ＠ Pike (-) developers forum 19 Apr '08

19 Apr '08

(or rather Getopt mark III, since I've already rewritten the current one, although no functionality was changed then) I've been working a bit on a new Argument parser, and would like some input. In reality there will be two different way of using the argument parser, which really doesn't share any code but is convenient to do at the same time. The first one is a "I just want to get this over with" kind of interface: void main(int num, array argv) { mapping args = Arg.parse(argv); argv = args[Arg.REST]; } The output will contain ([ "foo":1 ]) if the argument is --foo and ([ "foo":"bar" ]) if the argument is --foo=bar. There is no fancy stuff to handle default values (just or it with another mapping) or options that may or may not have values (e.g. -bar=foo will produce ([ "b":1, "a":1, "r":"foo" ]) and --foo x --bar will just produce ([ "foo":1 ]) and then stop processing the line). The other mode is the (supposedly) easy yet powerful mode that you would use for more mature applications. class Parser { inherit Arg.Options; Arg verbose = NoArg("-v")|NoArg("--verbose")|Env("VERBOSE"); Arg level = HasArg("-l")|HasArg("--level"); } void main(int n, array argv) { Parser p = Parser(argv); // Index magic. Some like it, some not so much. if( p->verbose ) werror("Level %s\n", p->level); } Which is extended in class Parser { // The name for now. inherit Arg.OptionsSupreme; Arg verbose = NoArg("-v")|NoArg("--verbose")|Env("VERBOSE"); // These are used in the automatically generated --help response. string help_pre = "This program is like awesum."; string verbose_help = "Increases the verbosity of the program."; // Called when/if verbose is set to a value. void verbose_cb(string arg) { werror("Verbosity is on.\n"); } } Does this match the long list of requirements that I've heard from others?

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Snapshot tarballs and packaging/debian
by Magnus Holmgren, FR Ryd (Nu med m�l och syfte) ＠ Pike (-) developers forum 03 Oct '07

03 Oct '07

I have a few questions relating to pike in Debian (as you may know, the previous maintainer has retired from Debian and orphaned his packages). I've figured out that one can get a fresh tarball from http://pike.ida.liu.se/generated/pikefarm/packages/7.6/latest. What's the difference between that and checking out from CVS and running "make source" (which is what I suspect Marek has done), if any? Is there any archive of such tarballs except for the official releases? How did the packaging/debian subdirectory originally come to be? Do you synchronize with the Debian package yourself or has Marek been sending you patches? I see that export.pike adds new records to packaging/debian/changelog. AFAICT, export.pike --tag first increments the build number (to an even number, typically), then tags, then increment the build number again, so that an even build number represents a known state of the source, whereas an odd build number can include any number of commits inbetween.

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Re: debian packages of 7.6.112
by Magnus Holmgren, exim.org ＠ Pike developers forum 26 Sep '07

26 Sep '07

Er, wait. It's not in _/usr/lib_, which is why you use $LD_LIBRARY_PATH to point to it. I guess pike could set it somewhere...

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Re: how to stop an iterator
by H. William Welliver III 26 Sep '07

26 Sep '07

> yeah, but next() is optional and not used by foreach There's no indication that next() is optional. At the very least, the documentation is somewhat lacking, if for no other reason than the api including two parallel sets of functions for interacting with the iterator, one of which is relatively more "standard" than the other without stating clearly which functions are actually used. I think most people who have used other languages with iterators will feel more comfortable with ->next() and friends, and be confused that they're not actually used. I know I was, and I'm probably not alone. > and += returns the iterator itself, so you can't return UNDEFINED > there. > since += never fails the only option is to test wether you still > have an > item there or not, and then ! is a good choice for that test. Well, you can very easily return undefined from `+=(), and it doesn't make any difference. That, at the very least, should have prompted an error, but instead, it kept right on running. I'm not sure that the semantics of this are appropriate, as the side effect is important (or should be, even if you're always supposed to return this_object() from `+=()). > it would be different if next() where the standard way of advancing > the > iterator. Well, it is the "standard" way, [by "standard", I mean the pattern employed by C++, Java, Objective-C, etc] Pike just happens to use operator overloading instead. Anyhow, my problem is solved. If I find time, I may update the documentation to be a little more clear about what's required and what's optional. Bill

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how to stop an iterator
by H. William Welliver III 26 Sep '07

26 Sep '07

I'm writing an iterator and under 7.7.34 (at least), I can't seem to get a loop using it to end, even though next() and `+=() both return UNDEFINED at the end, but the foreach loop doesn't ever seem to end. Am I missing something? Bill

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static variables with function scope
by Henrik Grubbstr�m (Lysator) ＠ Pike (-) developers forum 18 Sep '07

18 Sep '07

Hi. Some of you may have noticed that I implemented static variables with function scope a day or two ago. Example: int inc() { static int counter; return counter++; } The problem in Pike is that the intended lifetime of the variable isn't always obvious; consider nested classes: class X { int inc() { static int counter; return counter++; } } int main() { function(:int) X1 = X()->inc; function(:int) X2 = X()->inc; write("X1:%O,%O\n" "X2:%O\n", X1(), X1(), X2()); } Should the above output X1:0,1 X2:0, or X1:0,1 X2:2? ie should the variable be stored in X or in the top-level class? Pike also has nested functions; consider: function(:int) X() { int inc() { static int counter; return counter++; }; return inc; } int main() { function(:int) X1 = X(); function(:int) X2 = X(); write("X1:%O,%O\n" "X2:%O\n", X1(), X1(), X2()); } Same question. I believe that the most useful would be to store the variable in the closest surrounding scope (ie X1:0,1 X2:0 for both of the above), and then have some extra syntax for specifying some other scope. The question is what the syntax should be? Any suggestions?

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Pike conference 2007 - immediate release
by Matt Hardy - Webhaven via Martin Baehr 14 Sep '07

14 Sep '07

(forwarding this for matt, martin) Greetings, I am pleased to inform everyone concerned that the most preferred dates have been confirmed and facilities booked in Copenhagen, Denmark. 14 + 15 + 16 November 2007. First 2 days will be located at Copenhagen University. Last official day is at a carrier neutral datacentre also located in Copenhagen. Further days, for those who have time to stay longer, are TBA, depending on interest. I now hope everyone can look at calendars to ensure they have adequate time to attend the official program, it will be a very good chance to carry on discussions from last year in Riga, as well as discuss new developments undertaken since. All submissions for presentation or discussion topics are welcome. Please forward your submissions to the list, and/or you can attach documents by email to matt(a)webhaven.eu We will construct a 2007 website and publish a clear program for the 3 days. Pike Conference 2007 Copenhagen, Denmark ---->8------ if (Human.Programmer("meaning you")->wants_to_go()) { go(); } ----8<------

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Structured data mk III
by Henrik Grubbstr�m (Lysator) ＠ Pike (-) developers forum 02 Sep '07

02 Sep '07

I've just made some experiments for a replacement to ADT.struct and ADT.Struct: > program struct = >> ADT.Serialize.SimpleStruct("struct", >> ADT.Serialize.Int32, "integer", >> ADT.Serialize.SimpleStruct("substruct", >> ADT.Serialize.String, "data" >> ), "sub"); > object o = struct(14); > indices(o); (1) Result: ({ /* 5 elements */ "encode", "decode", "_integer", "integer", "sub" }) > o->integer; (2) Result: 14 > o->sub; (3) Result: substruct() > o->sub->data = "foobar"; (4) Result: "foobar" A decent encoding API is easy: > o->encode(); (5) Result: "\0\0\0\16foobar" Now to the hard part; a streaming decoder API... As far as I know, there are two main approaches: * Pull -- the user sends a data source (eg a file object) to the object, and it's up to the object to actually read the data. * Push -- the user reads the data in segments (typically with non-blocking I/O), and pushes it into the object. The Pull API is the easiest to implement, but it has the following problems: * Does not support non-blocking I/O. * Error recovery is complicated (eg if the source is a pipe/socket). * Extra over-head for the common case where you already have read the data. The Push API on the other hand has the following problems: * How to find where to restart the decoding when more data arrives. * How to signal that more data is needed/too much data was received. Suggestions?

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Pike-devel September 2007