Re: How to provide editor environment on STDIN
On Tue, Sep 22, 2009 at 23:10, Harry Putnam rea...@newsguy.com wrote:
Chas. Owens chas.ow...@gmail.com writes:
How big of a chore would it be to include code into the script that
creates some kind of editor like environment and allows bash style
completion?
I'm a very low level perl coder.. and will need pointers to some clues
about how to get this done, and incorporated into my scripts.
In shell scripting, at least with bash, taking input from user is done
with `read line' but you can say 'read -e line' and the input is
suddenly done with bash completion.. and I think a few other niceties.
Is there something similar in perl?
snip
Take a look at [Term::Readline][1], [Term::Readline::GNU][2], and
[Term::Readline::Perl][3].
I'm sad to say after installing Term::ReadLine::Gnu and looking at the
the 1014 lines of perldoc Term::ReadLine::Gnu..
snip
Term::Readline is more for writing programs with prompts (e.g. bash).
If you want to give the user a full editor, why not just drop them
into vi:
#!/usr/bin/perl
use strict;
use warnings;
use File::Temp qw/tempfile/;
#this is the safest way to get a temporary filename
my $tmpfile = do {
my ($fh, $filename) = tempfile();
close $fh;
$filename;
};
my $editor = $ENV{EDITOR} || /usr/bin/vi;
system($editor, $tmpfile) == 0
or die error occured while trying to run editor\n;
my $contents = do {
local $/;
open my $fh, , $tmpfile
or die could not open $tmpfile: $!\n;
$fh;
};
unlink $tmpfile
or die could not delete $tmpfile: $!;
print you wrote: [$contents]\n;
--
Chas. Owens
wonkden.net
The most important skill a programmer can have is the ability to read.
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: mbtomh in perl?
Hi Alexey! On Tuesday 22 Sep 2009 16:56:42 Mishustin Alexey wrote: Hello, Is there a perl tool for converting mbox files to MH directories? Google found only a tool on tcl [1] and a perl tool for converting mbox to Maildir [2]. [1] - http://wiki.tcl.tk/15276 [2] - http://batleth.sapienti-sat.org/projects/mb2md/ If there isn't such a tool 'out of the box', evidently, I will need some help to rewrite the tcl script on perl... Try the Mail::Box module: http://search.cpan.org/dist/Mail-Box/ It seems to still be the best of breed in this regard from what some authoritative sources in the Perl Email Project told me. It is large and complicated, but gets the job done. Regards, Shlomi Fish -- - Shlomi Fish http://www.shlomifish.org/ My Aphorisms - http://www.shlomifish.org/humour.html Chuck Norris read the entire English Wikipedia in 24 hours. Twice. -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: mbtomh in perl?
9/23/2009, Shlomi Fish shlo...@iglu.org.il вы писали: Is there a perl tool for converting mbox files to MH directories? [snip] Try the Mail::Box module: http://search.cpan.org/dist/Mail-Box/ It seems to still be the best of breed in this regard from what some authoritative sources in the Perl Email Project told me. It is large and complicated, but gets the job done. Thank you, I'll try! -- Regards, Alex -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: Burnt Camel Club
On Tue, 2009-09-22 at 09:59 -0500, Bryan R Harris wrote: On Mon, Sep 21, 2009 at 10:09 PM, Randal L. Schwartz mer...@stonehenge.comwrote: Yup. I care when it might harm others. Otherwise, I tend not to talk... plenty of other people here to give answers. I only doublecheck answers anymore. Yes, that is why this list gets 5 emails on average per day and other comparable language lists gets 40. Remember, correlation does not imply causality. Maybe people get answers faster here. Or the archives already answer most questions. Or perl is easy enough to use that people don't have to ask a lot of questions. I've gotten some seriously impressive responses to my questions and am 10x the programmer I'd be without this list (though that may not be saying much). Keep it up and the hollier-than-though's will have the list to themselves eventually. The respect is earned. It wouldn't surprise me if Einstein didn't have much patience for criticism from those with short resumes... - B Volume isn't always quality. There are some lists around where a significant portion of the volume is the blind leading the blind. The rest is experts trying to clean up the mess. Here the emphasis seems to be a little more on not making a mess in the first place (ie, discouraging less than helpful answers). Both approaches have their place. FWIW, as a perl newbie I'm happy with the way things are done here. Given FOSS is supposed to be all about having fun, why don't we have a 'Friday Fun' challenge aimed at beginners? A once a week small coding challenge (posted by 'those that know'?) that should take no more than 5-10 mins covering 'Programming 101 in Perl' type material (ie, no deep magic!). Brownie points for any decent/reasonable solution posted by a beginner within 24 hours. Rotten eggs for those who do an 'elephant drowned in custard' type solution. With a bit of luck it might help those paddling in the baby pool to venture out a bit further. Another $0.02, Tim Bowden -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: Burnt Camel Club
I enjoyed writing my script in perl despite not being a computer programmer, I get my need done without much stress, hence no need to increase the mail volume on the list. Perl6 definitely will take me higher to programming. Perl is still the best for beginers at least you can write your novice script and even get a sample script on the web to solve your problem. On 9/23/09, Tim Bowden tim.bow...@mapforge.com.au wrote: On Tue, 2009-09-22 at 09:59 -0500, Bryan R Harris wrote: On Mon, Sep 21, 2009 at 10:09 PM, Randal L. Schwartz mer...@stonehenge.comwrote: Yup. I care when it might harm others. Otherwise, I tend not to talk... plenty of other people here to give answers. I only doublecheck answers anymore. Yes, that is why this list gets 5 emails on average per day and other comparable language lists gets 40. Remember, correlation does not imply causality. Maybe people get answers faster here. Or the archives already answer most questions. Or perl is easy enough to use that people don't have to ask a lot of questions. I've gotten some seriously impressive responses to my questions and am 10x the programmer I'd be without this list (though that may not be saying much). Keep it up and the hollier-than-though's will have the list to themselves eventually. The respect is earned. It wouldn't surprise me if Einstein didn't have much patience for criticism from those with short resumes... - B Volume isn't always quality. There are some lists around where a significant portion of the volume is the blind leading the blind. The rest is experts trying to clean up the mess. Here the emphasis seems to be a little more on not making a mess in the first place (ie, discouraging less than helpful answers). Both approaches have their place. FWIW, as a perl newbie I'm happy with the way things are done here. Given FOSS is supposed to be all about having fun, why don't we have a 'Friday Fun' challenge aimed at beginners? A once a week small coding challenge (posted by 'those that know'?) that should take no more than 5-10 mins covering 'Programming 101 in Perl' type material (ie, no deep magic!). Brownie points for any decent/reasonable solution posted by a beginner within 24 hours. Rotten eggs for those who do an 'elephant drowned in custard' type solution. With a bit of luck it might help those paddling in the baby pool to venture out a bit further. Another $0.02, Tim Bowden -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/ -- Sent from my mobile device -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Friday Fun [was: Burnt Camel Club]
Tim, Given FOSS is supposed to be all about having fun, why don't we have a 'Friday Fun' challenge aimed at beginners? I would absolutely LOVE such a challenge! Regards, Botond -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
RE: Testing with Selenium
From: Steve Bertrand Steve Bertrand wrote: Bob McConnell wrote: I have begun the task of automating functional tests for some of our web servers. I have had some success using Selenium IDE in Firefox to capture input sequences, exporting them to Perl scripts, then using the Se remote control server to execute them. But I have run into one minor problem. A basic test is to verify the error message returned when an invalid password is entered. This test script is shown below. I can run this as a simple test, or it can be part of a suite. The command line to manually run the suite is normally: perl -MTest::Harness -e @ARGV= map glob, @ARGV \ if $^O =~ /^MSWin/; runtests @ARGV; test/*.pl Unfortunately, yes this is running on a WinXP system. My problem is that we have multiple virtual hosts on that server, and I need to select a specific host for each run. So when I run the harness I need some way to pass the tst12.dev portion of the URL into each of the test scripts. I can't see any way with Test::Harness or Test::More to do this. If I can, then I have other parameters that need to be passed in as well. Do I understand you correctly in believing that you are trying to run specific tests against numerous hosts within a single test file? Appears as though I've totally misunderstood what you are after... After re-reading, it looks as though you are trying to execute multiple test 'files', and want to supply the hostname (and perhaps other params) into them. Yes? Yes, I have a 'tests' directory with a growing number of Selenium scripts that will become an automated regression test. Each time I run those scripts with Test::Harness I need to pass a server name to each script. There are other variables I would also like to control. On my test server there are three hosts that I maintain, which normally have the current and two previous builds of the application. After I add or modify a test script, or make a change to the current version, if there is a test failure I can then run the same test on the previous versions to find out if they produce the same failure. These test scripts will be checked into our SCM so the QA and production teams have access to them as well. In addition, those teams should be able to record and add scripts that recreate problems they find or any that are reported by clients. Once fixed, those tests will also become part of the regression suite. This reduces the time to run a reasonably complete regression test from most of a man-week to a couple of hours. Paul's suggestion of environment variables appears to be the only viable option I have seen so far. Bob McConnell -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Burnt camel etc. etc
I've been reading these posts with a great deal of interest. I don't know what much of the fuss is about (having joined this forum about 2 years back), but I will say that I have had some VERY helpful responses from experts and beginners alike. For the most part this list does a great job in helping newbies. It would be a shame to change things. JMTC, Anjan -- = anjan purkayastha, phd bioinformatics analyst whitehead institute for biomedical research nine cambridge center cambridge, ma 02142 purkayas [at] wi [dot] mit [dot] edu 703.740.6939
Re: Burnt camel etc. etc
On Wed, Sep 23, 2009 at 08:46, ANJAN PURKAYASTHA anjan.purkayas...@gmail.com wrote: I've been reading these posts with a great deal of interest. I don't know what much of the fuss is about (having joined this forum about 2 years back), but I will say that I have had some VERY helpful responses from experts and beginners alike. For the most part this list does a great job in helping newbies. It would be a shame to change things. JMTC, Anjan snip There is a continuum of help from here, I did your homework for you to RTFM. In the past, Perl mailing lists and irc tended toward RTFM. To combat this perceived unfriendliness, this list was created. Its charter is to be [closer to here, I did your homework for you][1] than RTFM in the hopes that this will cause timid newbies to stick around and join the larger community. This causes a predictable backlash from people who believe that giving a man a fish instead of teaching him to fish is wrong. There is also backlash from people who become frustrated or get their buttons pushed (such as the whole legal boilerplate at the bottom of emails thread that started recently). The backlash causes another predictable backlash from the people who want to keep the list clear of the earlier backlash and people who, ironically enough, oppose backlash at all. And so on. Here are the rules I try to live by on this list (note, I don't always succeed): 1. A starving man or woman can't pay attention to the lesson you are giving him or her. Give him or her a fish and teach him or her. 2. If someone keeps asking for fish and never pays attention to the lesson, let him or her starve. 3. It is better to not post than to post angry. 4. Bad advice and answers must be corrected, but try to do it nicely. 5. Ask questions, don't make assumptions (I am really bad at this one). 6. Answer the [real question][2], but beware of number 5. [1] : without devolving into here, I did your homework for you [2] : this one is tricky, if some one asks how to write mergesort in Perl, they probably want the builtin sort function instead, but it might be that they need to sort something that won't fit in memory. -- Chas. Owens wonkden.net The most important skill a programmer can have is the ability to read. -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
decimal to binary?
I need to convert a number like this: -3205.0569059 ... into an 8-byte double (big and little endian), e.g. 4f 3e 52 00 2a bc 93 d3 (I just made up those 8 byte values). Is this easy in perl? Are long and short ints easy as well? Thanks! - Bryan -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
RE: decimal to binary?
From: Bryan R Harris I need to convert a number like this: -3205.0569059 ... into an 8-byte double (big and little endian), e.g. 4f 3e 52 00 2a bc 93 d3 (I just made up those 8 byte values). Is this easy in perl? Are long and short ints easy as well? The sprintf() family is your friend. Bob McConnell -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: decimal to binary?
BM == Bob McConnell r...@cbord.com writes: BM From: Bryan R Harris I need to convert a number like this: -3205.0569059 ... into an 8-byte double (big and little endian), e.g. 4f 3e 52 00 2a BM bc 93 d3 (I just made up those 8 byte values). Is this easy in perl? Are long and short ints easy as well? BM The sprintf() family is your friend. that will only generate text (hex and other formats). he needs pack which does exactly what he wants. read perlpacktut for a tutorial on pack/unpack and then perlfunc -f pack for the reference on it. pack can take a perl float and make a string of the internal representation in either endian order. for some real world examples of doing that, check out the code in Sort::Maker which packs floats into strings and deals with endian issues too. uri -- .signature_stem -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: decimal to binary?
I need to convert a number like this: -3205.0569059 ... into an 8-byte double (big and little endian), e.g. 4f 3e 52 00 2a bc 93 d3 (I just made up those 8 byte values). Is this easy in perl? Are long and short ints easy as well? The sprintf() family is your friend. I see %x (unsigned integer, in hexadecimal) and %f (floating-point number, in fixed decimal notation), but nothing about doubles, endianness, etc. I checked both my perl bookshelf and perldoc on this so far with no luck... - Bryan -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: decimal to binary?
Bryan R Harris wrote: I need to convert a number like this: -3205.0569059 ... into an 8-byte double (big and little endian), e.g. 4f 3e 52 00 2a bc 93 d3 (I just made up those 8 byte values). Is this easy in perl? Are long and short ints easy as well? $ perl -le'print unpack H*, pack d, -3205.0569059' e626c5221d0aa9c0 John -- The programmer is fighting against the two most destructive forces in the universe: entropy and human stupidity. -- Damian Conway -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
RE: decimal to binary?
From: Uri Guttman BM == Bob McConnell r...@cbord.com writes: BM From: Bryan R Harris I need to convert a number like this: -3205.0569059 ... into an 8-byte double (big and little endian), e.g. 4f 3e 52 00 2a BM bc 93 d3 (I just made up those 8 byte values). Is this easy in perl? Are long and short ints easy as well? BM The sprintf() family is your friend. that will only generate text (hex and other formats). he needs pack which does exactly what he wants. read perlpacktut for a tutorial on pack/unpack and then perlfunc -f pack for the reference on it. That statement just confuses me. His initial value of -3205.0569059 is also text. It is the human readable representation of the number, and is not anything like what it looks like inside the computer. He just asked for a different format for that text. Why is sprintf not a reasonable way to do that? Bob McConnell -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: decimal to binary?
From: Uri Guttman BM == Bob McConnell r...@cbord.com writes: BM From: Bryan R Harris I need to convert a number like this: -3205.0569059 ... into an 8-byte double (big and little endian), e.g. 4f 3e 52 00 2a BM bc 93 d3 (I just made up those 8 byte values). Is this easy in perl? Are long and short ints easy as well? BM The sprintf() family is your friend. that will only generate text (hex and other formats). he needs pack which does exactly what he wants. read perlpacktut for a tutorial on pack/unpack and then perlfunc -f pack for the reference on it. That statement just confuses me. His initial value of -3205.0569059 is also text. It is the human readable representation of the number, and is not anything like what it looks like inside the computer. He just asked for a different format for that text. Why is sprintf not a reasonable way to do that? The 8 bytes is an IEEE 754-2008 formatted number -- see here for an explanation: http://en.wikipedia.org/wiki/Double_precision It's not just a simple hex of a decimal... You've got an exponent and a sign encoded in there too. I'm still reading the perlpacktut, but I'm hoping it'll get me to that. - Bryan -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: decimal to binary?
BM == Bob McConnell r...@cbord.com writes: BM From: Uri Guttman BM == Bob McConnell r...@cbord.com writes: BM From: Bryan R Harris I need to convert a number like this: -3205.0569059 ... into an 8-byte double (big and little endian), e.g. 4f 3e 52 BM 00 2a BM bc 93 d3 (I just made up those 8 byte values). Is this easy in perl? Are long and short ints easy as well? BM The sprintf() family is your friend. that will only generate text (hex and other formats). he needs pack which does exactly what he wants. read perlpacktut for a tutorial on pack/unpack and then perlfunc -f pack for the reference on it. BM That statement just confuses me. His initial value of -3205.0569059 is BM also text. It is the human readable representation of the number, and is BM not anything like what it looks like inside the computer. He just asked BM for a different format for that text. Why is sprintf not a reasonable BM way to do that? he said number. perl will automatically convert a string number to a float. but he wants access to the bytes in that float (hence his mentioning of endian). perl can store a float, integer or string in a scalar. but the float can only be used as a number, you can't get at its bytes. pack solves that problem. uri -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: decimal to binary?
BRH == Bryan R Harris bryan_r_har...@raytheon.com writes: From: Uri Guttman BM == Bob McConnell r...@cbord.com writes: BM From: Bryan R Harris I need to convert a number like this: -3205.0569059 ... into an 8-byte double (big and little endian), e.g. 4f 3e 52 00 2a BM bc 93 d3 (I just made up those 8 byte values). Is this easy in perl? Are long and short ints easy as well? BM The sprintf() family is your friend. that will only generate text (hex and other formats). he needs pack which does exactly what he wants. read perlpacktut for a tutorial on pack/unpack and then perlfunc -f pack for the reference on it. That statement just confuses me. His initial value of -3205.0569059 is also text. It is the human readable representation of the number, and is not anything like what it looks like inside the computer. He just asked for a different format for that text. Why is sprintf not a reasonable way to do that? BRH The 8 bytes is an IEEE 754-2008 formatted number -- see here for an BRH explanation: BRH http://en.wikipedia.org/wiki/Double_precision BRH It's not just a simple hex of a decimal... You've got an exponent and a BRH sign encoded in there too. BRH I'm still reading the perlpacktut, but I'm hoping it'll get me to that. pack will do it. as i said, i am doing that very thing in Sort::Maker. it packs floats into strings for using in a string comparison for sorting. uri -- .signature_stem -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: How to provide editor environment on STDIN
Chas. Owens chas.ow...@gmail.com writes: On Tue, Sep 22, 2009 at 23:10, Harry Putnam rea...@newsguy.com wrote: Chas. Owens chas.ow...@gmail.com writes: How big of a chore would it be to include code into the script that creates some kind of editor like environment and allows bash style completion? I'm a very low level perl coder.. and will need pointers to some clues about how to get this done, and incorporated into my scripts. In shell scripting, at least with bash, taking input from user is done with `read line' but you can say 'read -e line' and the input is suddenly done with bash completion.. and I think a few other niceties. Is there something similar in perl? snip Take a look at [Term::Readline][1], [Term::Readline::GNU][2], and [Term::Readline::Perl][3]. I'm sad to say after installing Term::ReadLine::Gnu and looking at the the 1014 lines of perldoc Term::ReadLine::Gnu.. snip Haa... yes of course a much smarter approach thanks.. I guess there would be serious portability problems on any of the windows os's though. Thankfully I don't use this script there. -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: decimal to binary?
On Wed, Sep 23, 2009 at 15:32, Bob McConnell r...@cbord.com wrote: From: Uri Guttman BM == Bob McConnell r...@cbord.com writes: BM From: Bryan R Harris I need to convert a number like this: -3205.0569059 ... into an 8-byte double (big and little endian), e.g. 4f 3e 52 00 2a BM bc 93 d3 (I just made up those 8 byte values). Is this easy in perl? Are long and short ints easy as well? BM The sprintf() family is your friend. that will only generate text (hex and other formats). he needs pack which does exactly what he wants. read perlpacktut for a tutorial on pack/unpack and then perlfunc -f pack for the reference on it. That statement just confuses me. His initial value of -3205.0569059 is also text. It is the human readable representation of the number, and is not anything like what it looks like inside the computer. He just asked for a different format for that text. Why is sprintf not a reasonable way to do that? snip Because sprintf %16x, .5 returns and you can't recover .5 from that. On the other hand you can say: #!/usr/bin/perl use strict; use warnings; my $n= -3205.0569059; my $packed = pack d, $n; my $hex = unpack H*, $packed; my $unpacked = unpack d, pack H*, $hex; print n= $n\n, packed = $packed\n, hex = $hex\n, unpacked = $unpacked\n; -- Chas. Owens wonkden.net The most important skill a programmer can have is the ability to read. -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
RE: decimal to binary?
From: Bryan R Harris From: Uri Guttman BM == Bob McConnell r...@cbord.com writes: BM From: Bryan R Harris I need to convert a number like this: -3205.0569059 ... into an 8-byte double (big and little endian), e.g. 4f 3e 52 00 2a BM bc 93 d3 (I just made up those 8 byte values). Is this easy in perl? Are long and short ints easy as well? BM The sprintf() family is your friend. that will only generate text (hex and other formats). he needs pack which does exactly what he wants. read perlpacktut for a tutorial on pack/unpack and then perlfunc -f pack for the reference on it. That statement just confuses me. His initial value of -3205.0569059 is also text. It is the human readable representation of the number, and is not anything like what it looks like inside the computer. He just asked for a different format for that text. Why is sprintf not a reasonable way to do that? The 8 bytes is an IEEE 754-2008 formatted number -- see here for an explanation: http://en.wikipedia.org/wiki/Double_precision It's not just a simple hex of a decimal... You've got an exponent and a sign encoded in there too. OK, that I can understand. However, I don't see where that was expressed or implied in the original query. Are you assuming that every current architecture and Perl implementation uses that format to store double precision numbers? Is that a safe assumption? Bob McConnell -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: decimal to binary?
BM == Bob McConnell r...@cbord.com writes: BM OK, that I can understand. However, I don't see where that was BM expressed or implied in the original query. Are you assuming that BM every current architecture and Perl implementation uses that BM format to store double precision numbers? Is that a safe BM assumption? ieee float format is about the only way anyone does floats today. but pack actually doesn't even care about the float format. it just copies the internal float to a place where it can be accessed as a string of bytes (the string slot in the scalar). you can take any byte string you want and unpack back into the float slot. the only restriction is the size and that is usually 8 bytes (a double which is perl's standard float size). pack supports single precision (4 bytes) as well as long doubles if your machine supports them. as for whether this is what the OP wanted, note that he since posted that he is reading perlpacktut for his answers. someone else already posted the pack format needed but i wanted him to rtfm and learn more about pack. uri -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: decimal to binary?
Bryan R Harris wrote: I need to convert a number like this: -3205.0569059 ... into an 8-byte double (big and little endian), e.g. 4f 3e 52 00 2a bc 93 d3 (I just made up those 8 byte values). Is this easy in perl? Are long and short ints easy as well? $ perl -le'print unpack H*, pack d, -3205.0569059' e626c5221d0aa9c0 Maybe this is just my own ignorance on big-endian vs. little endian, but this code: print big-endian: , unpack(H*, pack(d, -3205.0569059)), \n; print little-endian: , unpack(h*, pack(d, -3205.0569059)), \n; prints: big-endian: e626c5221d0aa9c0 little-endian: 6e625c22d1a09a0c ... when I expected the little endian to look more like: c0 a9 0a 1d 22 c5 26 e6 (spacing for readability) Did I do it wrong (i.e. is h* the wrong string?), or am I confused on how big vs. little endian works? Thanks again for the help!! This list is terrific! - Bryan -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: decimal to binary?
On Wed, Sep 23, 2009 at 17:00, Bryan R Harris bryan_r_har...@raytheon.com wrote: Bryan R Harris wrote: I need to convert a number like this: -3205.0569059 ... into an 8-byte double (big and little endian), e.g. 4f 3e 52 00 2a bc 93 d3 (I just made up those 8 byte values). Is this easy in perl? Are long and short ints easy as well? $ perl -le'print unpack H*, pack d, -3205.0569059' e626c5221d0aa9c0 Maybe this is just my own ignorance on big-endian vs. little endian, but this code: print big-endian: , unpack(H*, pack(d, -3205.0569059)), \n; print little-endian: , unpack(h*, pack(d, -3205.0569059)), \n; prints: big-endian: e626c5221d0aa9c0 little-endian: 6e625c22d1a09a0c ... when I expected the little endian to look more like: c0 a9 0a 1d 22 c5 26 e6 (spacing for readability) Did I do it wrong (i.e. is h* the wrong string?), or am I confused on how big vs. little endian works? snip h* and H* have nothing to do with endianness. From the docs: h A hex string (low nybble first). H A hex string (high nybble first). Endianness occurs at the byte level, not the nybble level. -- Chas. Owens wonkden.net The most important skill a programmer can have is the ability to read. -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: decimal to binary?
BRH == Bryan R Harris bryan_r_har...@raytheon.com writes: BRH Maybe this is just my own ignorance on big-endian vs. little endian, but BRH this code: BRH print big-endian: , unpack(H*, pack(d, -3205.0569059)), \n; BRH print little-endian: , unpack(h*, pack(d, -3205.0569059)), \n; BRH prints: BRH big-endian: e626c5221d0aa9c0 BRH little-endian: 6e625c22d1a09a0c note that those are the same bytes but each byte is printed with different ordering for the hex digits. the docs say this: h A hex string (low nybble first). H A hex string (high nybble first). and a nybble (or nibble) is a single hex digit of 4 bits and there are two in a byte. the h vs H only changes the nibble order in a byte. this has nothing to do with endian issues which are a byte ordering thing. pack doesn't have a direct way to deal with endians with floats. you can just use reverse on the byte string to control that. that is what i do in Sort::Maker for this. did you look at that module yet? as i keep saying it does exactly what you are trying to do so you can learn from it. uri -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: decimal to binary?
Bryan R Harris wrote:
John W. Krahn wrote:
Bryan R Harris wrote:
I need to convert a number like this: -3205.0569059
... into an 8-byte double (big and little endian), e.g. 4f 3e 52 00 2a bc 93
d3 (I just made up those 8 byte values).
Is this easy in perl? Are long and short ints easy as well?
$ perl -le'print unpack H*, pack d, -3205.0569059'
e626c5221d0aa9c0
Maybe this is just my own ignorance on big-endian vs. little endian, but
this code:
print big-endian: , unpack(H*, pack(d, -3205.0569059)), \n;
print little-endian: , unpack(h*, pack(d, -3205.0569059)), \n;
prints:
big-endian: e626c5221d0aa9c0
little-endian: 6e625c22d1a09a0c
... when I expected the little endian to look more like:
c0 a9 0a 1d 22 c5 26 e6 (spacing for readability)
Did I do it wrong (i.e. is h* the wrong string?), or am I confused on how
big vs. little endian works?
The difference between 'h' and 'H' has nothing to do with endianness:
perldoc -f pack
[ SNIP ]
h A hex string (low nybble first).
H A hex string (high nybble first).
A nybble is half of a byte so the only thing exchanged is the order of
each byte's two halves.
AFAIK floating point numbers don't have endianness (but I may be wrong.)
(Besides, in the above example, endianness would be on the pack('d')
side of the equation.)
John
--
The programmer is fighting against the two most
destructive forces in the universe: entropy and
human stupidity. -- Damian Conway
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: decimal to binary?
JWK == John W Krahn jwkr...@shaw.ca writes:
JWK AFAIK floating point numbers don't have endianness (but I may be wrong.)
JWK (Besides, in the above example, endianness would be on the pack('d')
JWK side of the equation.)
floats are no different than integers in that you must select the
ordering of their bytes when stored in ram. this is done naturally at
the machine level but if you want to control endianess with floats in
perl you need to use reverse at some point.
uri
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: decimal to binary?
Bryan R Harris wrote: Bryan R Harris wrote: I need to convert a number like this: -3205.0569059 ... into an 8-byte double (big and little endian), e.g. 4f 3e 52 00 2a bc 93 d3 (I just made up those 8 byte values). Is this easy in perl? Are long and short ints easy as well? $ perl -le'print unpack H*, pack d, -3205.0569059' e626c5221d0aa9c0 Maybe this is just my own ignorance on big-endian vs. little endian, but this code: print big-endian: , unpack(H*, pack(d, -3205.0569059)), \n; print little-endian: , unpack(h*, pack(d, -3205.0569059)), \n; prints: big-endian: e626c5221d0aa9c0 little-endian: 6e625c22d1a09a0c ... when I expected the little endian to look more like: c0 a9 0a 1d 22 c5 26 e6 (spacing for readability) Did I do it wrong (i.e. is h* the wrong string?), or am I confused on how big vs. little endian works? Thanks again for the help!! This list is terrific! From `perldoc -f pack`: Real numbers (floats and doubles) are in the native machine format only; due to the multiplicity of floating formats around, and the lack of a standard network representation, no facility for interchange has been made. This means that packed floating point data written on one machine may not be readable on another - even if both use IEEE floating point arithmetic (as the endian-ness of the memory representation is not part of the IEEE spec). See also perlport. -- Just my 0.0002 million dollars worth, Shawn Programming is as much about organization and communication as it is about coding. I like Perl; it's the only language where you can bless your thingy. -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: decimal to binary?
On Wed, Sep 23, 2009 at 15:53, Bob McConnell r...@cbord.com wrote: snip OK, that I can understand. However, I don't see where that was expressed or implied in the original query. Are you assuming that every current architecture and Perl implementation uses that format to store double precision numbers? Is that a safe assumption? Bob McConnell snip No, it is not safe to assume that the value you get from pack will work on another platform. The pack function claims that d creates a native-floating point number as a string of bytes. This means you are dependent on the native implementations of floating point numbers being the same between systems. However, a quick sample of OS X 10.5 (x86), a variety of Linuxes (x86), Win32 (x86), and FreeBsd (x86) shows that it works across a wide swath of what one generally works with. The Power PC machine machine I have access to (running OS X) works if you reverse the bytes. -- Chas. Owens wonkden.net The most important skill a programmer can have is the ability to read. -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: Burnt Camel Club
On Tue, Sep 22, 2009 at 08:55:32AM -0500, Ian wrote: On Mon, Sep 21, 2009 at 10:09 PM, Randal L. Schwartz mer...@stonehenge.comwrote: Yup. I care when it might harm others. Otherwise, I tend not to talk... plenty of other people here to give answers. I only doublecheck answers anymore. Yes, that is why this list gets 5 emails on average per day and other comparable language lists gets 40. Keep it up and the hollier-than-though's will have the list to themselves eventually. Don't kid your self as long as there are people like me who are trying to get a handle on Perl, this list will stay active. One of the best math teachers I had in high school was a birch and hadn't changed since she taught my ma. Mom and I both learned math from her though. Ian Mike -- Satisfied user of Linux since 1997. O ascii ribbon campaign - stop html mail - www.asciiribbon.org -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: best way to get number of elements in list value
On Tue, Sep 22, 2009 at 05:09:26AM -0400, Shawn H Corey wrote:
Roman Makurin wrote:
Hi All!
right now im doing it in following way:
$size = @{[func_that_return_list_value]};
is there any best way to do it ?
See `perldoc -f scalar` http://perldoc.perl.org/functions/scalar.html
I read the perldoc on scaler and then tried every combination
I could think of:
perl -le ' sub farr{ return qw( k l m ); }
$a = @{[farr]};
$b = scalar farr;
$c = scalar (farr);
$d = scalar [farr];
$e = scalar @{farr};
$f = scalar @{[farr]};
$g = () = farr;
print \n\$a = $a, \$b = $b, \$c = $c, \$d = $d, \$e = $e, \$f = $f, \$g = $g;'
$a = 3, $b = m, $c = m, $d = ARRAY(0x814f8e4), $e = 0, $f = 3, $g = 3
Unless there is a syntax I've missed, only a, f g give the desired answer.
To my thinking a is clearly preferable to f but the winner has to be g.
=()= is much more legible than @{[]}, less prone to mistyping.
Thank you Paul Johnson for bringing this to my attention.
The original question was what's 'best'.
Does anyone know of a case where one of these expressions would fail?
TIA,
Mike
--
Satisfied user of Linux since 1997.
O ascii ribbon campaign - stop html mail - www.asciiribbon.org
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: best way to get number of elements in list value
On Wed, Sep 23, 2009 at 19:16, Mike McClain mike.j...@nethere.com wrote:
On Tue, Sep 22, 2009 at 05:09:26AM -0400, Shawn H Corey wrote:
Roman Makurin wrote:
Hi All!
right now im doing it in following way:
$size = @{[func_that_return_list_value]};
is there any best way to do it ?
See `perldoc -f scalar` http://perldoc.perl.org/functions/scalar.html
I read the perldoc on scaler and then tried every combination
I could think of:
perl -le ' sub farr{ return qw( k l m ); }
$a = @{[farr]};
$b = scalar farr;
$c = scalar (farr);
$d = scalar [farr];
$e = scalar @{farr};
$f = scalar @{[farr]};
$g = () = farr;
print \n\$a = $a, \$b = $b, \$c = $c, \$d = $d, \$e = $e, \$f = $f, \$g =
$g;'
$a = 3, $b = m, $c = m, $d = ARRAY(0x814f8e4), $e = 0, $f = 3, $g = 3
Unless there is a syntax I've missed, only a, f g give the desired answer.
To my thinking a is clearly preferable to f but the winner has to be g.
=()= is much more legible than @{[]}, less prone to mistyping.
Thank you Paul Johnson for bringing this to my attention.
The original question was what's 'best'.
Does anyone know of a case where one of these expressions would fail?
snip
Both the a and g cases only work because the assignment provides
scalar context. Failure to recognize this may cause you to write
my %h = (
a = @{[farr]},
g = () = farr,
);
which results in either an error (if farr returns an even number), or
worse, a very odd hash:
my %h = (
'a' = 'k',
'l' = 'm',
'g' = undef
);
The solution is to force scalar context with scalar:
#!/usr/bin/perl
use strict;
use warnings;
use Data::Dumper;
sub farr { return qw/k l m/ }
my %h = (
a = scalar @{[farr]},
g = scalar(() = farr),
);
print Dumper \%h;
Of course, the best solution is to make farr context aware with the
poorly named [wantarray][1]:
#!/usr/bin/perl
use strict;
use warnings;
use Data::Dumper;
sub farr {
my @a = qw/k l m/;
return wantarray ? @a : scalar @a;
}
my @list = farr;
my $count = farr;
print [...@list] has $count items\n;
my %h = (
h = scalar farr,
);
print Dumper \%h;
[1] : http://perldoc.perl.org/functions/wantarray.html
--
Chas. Owens
wonkden.net
The most important skill a programmer can have is the ability to read.
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: decimal to binary?
BRH == Bryan R Harris bryan_r_har...@raytheon.com writes: BRH Maybe this is just my own ignorance on big-endian vs. little endian, but BRH this code: BRH print big-endian: , unpack(H*, pack(d, -3205.0569059)), \n; BRH print little-endian: , unpack(h*, pack(d, -3205.0569059)), \n; BRH prints: BRH big-endian: e626c5221d0aa9c0 BRH little-endian: 6e625c22d1a09a0c note that those are the same bytes but each byte is printed with different ordering for the hex digits. the docs say this: h A hex string (low nybble first). H A hex string (high nybble first). and a nybble (or nibble) is a single hex digit of 4 bits and there are two in a byte. the h vs H only changes the nibble order in a byte. this has nothing to do with endian issues which are a byte ordering thing. pack doesn't have a direct way to deal with endians with floats. you can just use reverse on the byte string to control that. that is what i do in Sort::Maker for this. did you look at that module yet? as i keep saying it does exactly what you are trying to do so you can learn from it. Ah, this is the key I was missing! Thanks. Now I'm getting this: value: -3205.0569059 big-endian: c0 a9 0a 1d 22 c5 26 e6 little-endian: e6 26 c5 22 1d 0a a9 c0 I'm not sure whether I have my endians switched, but I'm putting my chances of being right here at a little better than 50%. =) (Actually, I see your $IS_BIG_ENDIAN check at the beginning of Sort::Maker, and borrowing that, I think my chances are much better now that I got it right.) As for looking at Sort::Maker, I have to admit I was a little scared at first. It's not obvious to me why you'd need to be packing doubles for a sort routine, and I feared I'd get lost in the code... That said, I found the reverse part and it looked easy, so that's what I needed. I think I'm good. Thanks again to all. Hope this makes good list-archives fodder. - Bryan -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Automating for the SNMPv3 query and trap
HI All, I want to write perl script to automate SNMPv3 query and traps. Is there any module that can be use for the same? Also what are the different functions for the query / MIB file compilation and traps? Please suggest -- Rachit Gupta r.rac...@gmail.com 91-9873242190
Re: How to provide editor environment on STDIN
Harry wrote:
In shell scripting, at least with bash, taking input from user is done
with `read line' but you can say 'read -e line' and the input is
suddenly done with bash completion.. and I think a few other niceties.
Is there something similar in perl?
Chas O. answered
snip
Take a look at [Term::Readline][1], [Term::Readline::GNU][2], and
[Term::Readline::Perl][3].
I'm sad to say after installing Term::ReadLine::Gnu and looking at the
the 1014 lines of perldoc Term::ReadLine::Gnu..
snip
[...] snipped nifty code.
Haa... yes of course a much smarter approach thanks..
I'm integrating this new stuff into my homeboy script. In that usage
I really want to write to a final target file with a certain format.
Like:
Keywords: SOME KEY WORDS ON THIS LINE
[Keydate:FORMATTED DATE]
any more content from the for the target file
So there is a `keyword' line followed by a formatted date line.
Followed by any other commentary, followed by a `' delimiter on a
line by itself.
The target file is a very basic data base where I keep snippets of info
I want to be able to find later. The file is thousands of lines long
so not something I want load.
Another homeboy script does a few different kinds of search functions
on this flat file db and spits out the hits along with the whole keywords
and date entry.
Below I've included a test script where I try to integrate your
suggestions and a version of your code that I've seriously meddled
with.
This is an edited down version of what would really go in the main
script.
I added the file extension only because I'll be using emacs as the
invoked editor and that extension will make emacs set a few handy
things that are useful in a plain text message, like line wrapping
and abbrev completions.
I tinkered around trying to use the notation you used in your example
on file opening:
( `open my $fh, , $tmpfile' ) and other places
but stumbled with it and finally reverted to something I'm used to.
Mainly to get this posted and have a chance to hear any other advice
you might have.
But on that notation point, when using a variable to represent the FH,
like in the notation you showed, how do you later refer to it in a
print statement when you want to direct the print to the FH? Like:
print FH something\n;
= * = * = * =
Here is a test script trying to integrate what you've shown but aim it
at an intended target. And format the input somewhat. Using the
first line of input as the `Keywords' line.
It works in my tests and will be a welcome improvement in that much
used script... but wondering if there are better ways to accomplish
the goal?
#!/usr/local/bin/perl
use strict;
use warnings;
use File::Temp qw/tempfile/;
my $ext = '.txt';
#this is the safest way to get a temporary filename
my $tmpfile = do {
my ($fh, $filename) = tempfile();
close $fh;
$filename;
};
$tmpfile = $tmpfile . $ext;
my $editor = $ENV{EDITOR} || /usr/bin/vim;
system($editor, $tmpfile) == 0
or die error occured while trying to run editor\n;
my @contents;
open(TMPFILE,$tmpfile)
or die could not open $tmpfile: $!\n;
## Where editor content is really headed
my $ActualTarget = './misc-snp';
open(ACTUAL_TARGET,$ActualTarget)
or die Can't open $ActualTarget : $!;
my $paddedds = '';
while(TMPFILE){
if($. == 1){
print ACTUAL_TARGET Keywords: $_;
next;
}
if($. == 2){
print ACTUAL_TARGET [Keydate: . PaddedDateStr() . ]\n$_;
$paddedds = TRUE;
next;
}
print ACTUAL_TARGET $_;
}
## If the padded date string didn't get printed yet, do so now.
if(!$paddedds){
print ACTUAL_TARGET [Keydate: . PaddedDateStr() . ]\n;
}
## Close the entry with double ampersands on a line by themselves.
print ACTUAL_TARGET \n;
close(ACTUAL_TARGET);
unlink $tmpfile
or die could not delete $tmpfile: $!;
sub PaddedDateStr {
my ($mon,$mday,$year,$hour,$min,$sec,$wday) =
(localtime(time))[4,3,5,2,1,0,6];
$year -= 100;
$mon += 1;
my $PaddedDateStr = sprintf %02d%02d%02d%s%02d%02d%02d%s%d, $mon,
$mday,$year,_,$hour,$min,$sec,_,$wday;
return $PaddedDateStr;
}
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
