Re: perl qstn...
Alejandro == Alejandro Imass a...@p2ee.org writes: Alejandro did you mean unless? ;-) Did you read this: Augh. I hit send just as I realized that's backwards. Need more caffiene. Swap the true and false blocks there. :) -- Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095 mer...@stonehenge.com URL:http://www.stonehenge.com/merlyn/ Smalltalk/Perl/Unix consulting, Technical writing, Comedy, etc. etc. See http://methodsandmessages.vox.com/ for Smalltalk and Seaside discussion ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: perl qstn...
On Fri, Apr 9, 2010 at 5:56 AM, Randal L. Schwartz mer...@stonehenge.com wrote: Alejandro == Alejandro Imass a...@p2ee.org writes: Alejandro did you mean unless? ;-) Did you read this: Augh. I hit send just as I realized that's backwards. Need more caffiene. Swap the true and false blocks there. :) Yeah, but _after_ I had pressed send . That sparked the comment that unless was a bad idea in C and then all helll broke loose lol -- Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095 mer...@stonehenge.com URL:http://www.stonehenge.com/merlyn/ Smalltalk/Perl/Unix consulting, Technical writing, Comedy, etc. etc. See http://methodsandmessages.vox.com/ for Smalltalk and Seaside discussion ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: perl qstn...
On Wed, 7 Apr 2010 19:15:05 -0600 Chad Perrin per...@apotheon.com wrote: On Wed, Apr 07, 2010 at 01:09:54PM +0100, RW wrote: On Tue, 6 Apr 2010 21:07:17 -0600 Chad Perrin per...@apotheon.com wrote: On Tue, Apr 06, 2010 at 01:20:49PM +0100, RW wrote: On Mon, 5 Apr 2010 19:55:44 -0600 Chad Perrin per...@apotheon.com wrote: On Mon, Apr 05, 2010 at 05:36:32PM +0100, RW wrote: There are more things in heav'n and earth, Horatio, than are dreamt of by designers of eagerly evaluated prefix notation languages. And most of them are obscure for good reasons. Just because a a syntax fits into a classification scheme doesn't make it a good idea. Shall we trade more trite sniping, or would you like to say something more substantive? You started it. 1. No, I used a misquote to lead into a lengthy explanation. You started with a patronising misquote implying ignorance of wider context. I'm not, I'm expressing an opinion that this is not a feature worth copying. Judging by your further disputations with Mr. Schwartz, I don't think I believe you. I can live with that. If I don't think it worth copying, I'm not going to like it in perl. That's not the same as telling you what you should and shouldn't do. I don't use perl or python all that much, and I wasn't aware of quite how religious an issue this is. I thought I was commenting on a perl feature, but it appears to have been interpreted as an attack on your faith. Frankly, if everybody just stuck to a purely natural order of decision approach to imperative language design, we would never even have developed structured programming. I have no idea what you trying to say here. I presume it must be some kind of straw man argument. It's not a straw man argument. Your presumption is wrong. Then your comment is simply noise. Most structured languages get by without the feature I'm referring to, and I've made it clear I'm not talking about ordering in any other context. ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: perl qstn...
On Tue, 6 Apr 2010 21:07:17 -0600 Chad Perrin per...@apotheon.com wrote: On Tue, Apr 06, 2010 at 01:20:49PM +0100, RW wrote: On Mon, 5 Apr 2010 19:55:44 -0600 Chad Perrin per...@apotheon.com wrote: On Mon, Apr 05, 2010 at 05:36:32PM +0100, RW wrote: There are more things in heav'n and earth, Horatio, than are dreamt of by designers of eagerly evaluated prefix notation languages. And most of them are obscure for good reasons. Just because a a syntax fits into a classification scheme doesn't make it a good idea. Shall we trade more trite sniping, or would you like to say something more substantive? You started it. Natural languages are mostly driven by spoken usage, in which people firm-up half-formed ideas as they speak - this is not a good model for programming languages. If you are hacking out a quick and dirty script it may be convenient to type the decision after the action, but it don't I think it promotes good quality software. This sounds exactly like the complaints Pythonistas use to explain why they have a deep hatred of Perl. If that's how you feel, I'd prefer you stop trying to tell me how Perl should work, and just use something else. I'm not, I'm expressing an opinion that this is not a feature worth copying. Imperative languages have a natural order of decision followed by action, and code is most easily readable if the syntax doesn't try to subvert that. . . . except when the natural order of decision varies significantly, such as when comparing functions with operators. It gets even more confusing when both functions and operators are actually methods in object oriented languages with an imperative design, because suddenly the difference between a function and an operator becomes purely arbitrary. There's nothing about arbitrariness that suggests a natural order. Expression are different. When you are trying to understand thousands of lines of code, the order of execution within an expression is fine detail, but the flow of execution is something that needs to be taken-in easily. It's kind of odd you rail against natural language then talk about I'm not railing again natural languages, I just don't think they have much relevance. imperative languages having a natural order -- which is, presumably, based on the expectations of people who have been conditioned to think that way by their use of natural language. No, it's conditioned by causality, and other mainstream programming languages. People juggle a lot of languages, being different for the sake of it isn't very helpful. Frankly, if everybody just stuck to a purely natural order of decision approach to imperative language design, we would never even have developed structured programming. I have no idea what you trying to say here. I presume it must be some kind of straw man argument. ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: perl qstn...
On Tue, Apr 06, 2010 at 09:01:10PM -0600, Chad Perrin wrote: On Tue, Apr 06, 2010 at 06:17:41PM -0400, Steve Bertrand wrote: On 2010.04.06 17:10, Randal L. Schwartz wrote: Now, on the other hand, emacs rules, vi sucks. :-) :-) ok, ok. I was on the side of Perl, and was content following this thread, but now I don't like you anymore :P heh ;) Steve I'm willing to let the emacs users have their emacs, and to enjoy my vi. I guess the longer name (emacs) suits people who like pressing more buttons to accomplish the same amount of work anyway. besides all this, someone can use vi easily with only one hand---or just a few fingers for those of us who still hunt-and-peck. with emacs, gotta have at least 17 hands. -- Chad Perrin [ original content licensed OWL: http://owl.apotheon.org ] -- Gary Kline kl...@thought.org http://www.thought.org Public Service Unix http://jottings.thought.org http://transfinite.thought.org The 7.79a release of Jottings: http://jottings.thought.org/index.php ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: perl qstn...
On Tue, Apr 6, 2010 at 5:10 PM, Randal L. Schwartz mer...@stonehenge.com wrote: Chuck == Chuck Swiger cswi...@mac.com writes: [...] Now, on the other hand, emacs rules, vi sucks. :-) :-) you got that right bud! oh, and the Perl stuff too ;-) -- Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095 mer...@stonehenge.com URL:http://www.stonehenge.com/merlyn/ Smalltalk/Perl/Unix consulting, Technical writing, Comedy, etc. etc. See http://methodsandmessages.vox.com/ for Smalltalk and Seaside discussion ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: perl qstn...
On Wed, Apr 07, 2010 at 01:09:54PM +0100, RW wrote: On Tue, 6 Apr 2010 21:07:17 -0600 Chad Perrin per...@apotheon.com wrote: On Tue, Apr 06, 2010 at 01:20:49PM +0100, RW wrote: On Mon, 5 Apr 2010 19:55:44 -0600 Chad Perrin per...@apotheon.com wrote: On Mon, Apr 05, 2010 at 05:36:32PM +0100, RW wrote: There are more things in heav'n and earth, Horatio, than are dreamt of by designers of eagerly evaluated prefix notation languages. And most of them are obscure for good reasons. Just because a a syntax fits into a classification scheme doesn't make it a good idea. Shall we trade more trite sniping, or would you like to say something more substantive? You started it. 1. No, I used a misquote to lead into a lengthy explanation. 2. Seriously? Are you not aware of how juvenile that sounds? Natural languages are mostly driven by spoken usage, in which people firm-up half-formed ideas as they speak - this is not a good model for programming languages. If you are hacking out a quick and dirty script it may be convenient to type the decision after the action, but it don't I think it promotes good quality software. This sounds exactly like the complaints Pythonistas use to explain why they have a deep hatred of Perl. If that's how you feel, I'd prefer you stop trying to tell me how Perl should work, and just use something else. I'm not, I'm expressing an opinion that this is not a feature worth copying. Judging by your further disputations with Mr. Schwartz, I don't think I believe you. Imperative languages have a natural order of decision followed by action, and code is most easily readable if the syntax doesn't try to subvert that. . . . except when the natural order of decision varies significantly, such as when comparing functions with operators. It gets even more confusing when both functions and operators are actually methods in object oriented languages with an imperative design, because suddenly the difference between a function and an operator becomes purely arbitrary. There's nothing about arbitrariness that suggests a natural order. Expression are different. When you are trying to understand thousands of lines of code, the order of execution within an expression is fine detail, but the flow of execution is something that needs to be taken-in easily. This doesn't change anything I said. It's kind of odd you rail against natural language then talk about I'm not railing again natural languages, I just don't think they have much relevance. It's kind of odd you rail against natural language *in this context*. I thought in this context was obvious. imperative languages having a natural order -- which is, presumably, based on the expectations of people who have been conditioned to think that way by their use of natural language. No, it's conditioned by causality, and other mainstream programming languages. People juggle a lot of languages, being different for the sake of it isn't very helpful. Who said anything about being different for the sake of being different? If you find it too difficult to actually respond to what I said, please refrain from responding. Frankly, if everybody just stuck to a purely natural order of decision approach to imperative language design, we would never even have developed structured programming. I have no idea what you trying to say here. I presume it must be some kind of straw man argument. It's not a straw man argument. Your presumption is wrong. I have no idea how what I said could not be perfectly obvious. It's pretty clear. -- Chad Perrin [ original content licensed OWL: http://owl.apotheon.org ] pgpv6MIox8pkk.pgp Description: PGP signature
Re: perl qstn...
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On 06/04/2010 02:55:44, Chad Perrin wrote: 3. lazy evaluation, where the (result) is not evaluated until it is needed, which gives the interpreter plenty of time to notice there's an unless immediately following it Obviously, the real answer in the case of Ruby and Perl falls somewhere around 1.5, but 3 is still a believable-sounding excuse, and perfectly acceptable to me. perl (and ruby) are byte-compiled languages, not interpreted languages (like sh). All ordering variations on if and unless statements should end up using pretty much the same sequence of opcodes once parsed and compiled. Cheers, Matthew - -- Dr Matthew J Seaman MA, D.Phil. 7 Priory Courtyard Flat 3 PGP: http://www.infracaninophile.co.uk/pgpkey Ramsgate Kent, CT11 9PW -BEGIN PGP SIGNATURE- Version: GnuPG/MacGPG2 v2.0.14 (Darwin) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAku61VIACgkQ8Mjk52CukIwLPQCfXW15dHTRMRfIENyT//OrzzAz qYAAnjYjiRsS2jq9XaJ2xN15sM1BDc6K =3PnR -END PGP SIGNATURE- ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: perl qstn...
On Mon, 5 Apr 2010 19:55:44 -0600 Chad Perrin per...@apotheon.com wrote: On Mon, Apr 05, 2010 at 05:36:32PM +0100, RW wrote: IMO this is a bad mistake that other languages were quite right not to copy - a test shouldn't come after a block of code unless it's evaluated after the block (as in repeat...until) There are more things in heav'n and earth, Horatio, than are dreamt of by designers of eagerly evaluated prefix notation languages. And most of them are obscure for good reasons. Just because a a syntax fits into a classification scheme doesn't make it a good idea. Natural languages are mostly driven by spoken usage, in which people firm-up half-formed ideas as they speak - this is not a good model for programming languages. If you are hacking out a quick and dirty script it may be convenient to type the decision after the action, but it don't I think it promotes good quality software. Imperative languages have a natural order of decision followed by action, and code is most easily readable if the syntax doesn't try to subvert that. ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: perl qstn...
RW == RW rwmailli...@googlemail.com writes:
RW Imperative languages have a natural order of decision followed by
RW action, and code is most easily readable if the syntax doesn't try to
RW subvert that.
And yet, there's an equally valid argument that the most important
thing should stand out the most. In that sense, in the Perl statement:
warn x = $x, y = $y, z = $z\n
if $debug;
... the most important part is that it's printing something to stderr,
and what's being printed. It's only minor that it's only when
debugging, and luckily Perl lets us relegate that to the tail end of
the statement.
Now, if you argue oh, the most important thing there is 'if debug',
then fine, you'd write that as:
if ($debug) { warn ... }
And I'd be fine with that. But I tend to see that layout as a lot of
noise just to add a minor conditional. Or you could speak Perl
with a Shell accent, and say
$debug and warn ...;
Fine, that also works, and some part of your audience will hate you,
and another part will be totally cool with it.
But this *is* the reason There's More Than One Way To Do It in Perl.
You can write Perl that most naturally expresses what you believe
is important in the code.
If you don't like all this freedom, there's always Python. :)
--
Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095
mer...@stonehenge.com URL:http://www.stonehenge.com/merlyn/
Smalltalk/Perl/Unix consulting, Technical writing, Comedy, etc. etc.
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Re: perl qstn...
On Sun, 04 Apr 2010 02:01:53 -0700, Gary Kline kl...@thought.org wrote:
thanks for your url as well and the others to posted. but it seems
like overkill since i dont need any explicit option or argument. i
just need the script to tell me whether i have an arg or not.
following is something i've kept in one of my junk drawers from when i
was learning to write bourne sscripts. it uses the $[token] syntax
that determines whether there are Any args on the cmdline. if not,
the script prints a message and exits.
#!/bin/sh
if [ $# -eq 0 ]
then
echo No args; need filename.
else
echo $1
fi
After a couple hours experimentation, the following does the same for my
perl scripts:
#!/usr/bin/perl
$argc = @ARGV;
if (! $argc ) {
printf(No args; need filename.\n);
}
else {
printf(%s\n, @ARGV);
}
Yes, that's very close to the sh(1) version. Perl's behavior in this
case is described in the 'perlvar' manpage:
@ARGV The array @ARGV contains the command-line arguments intended
for the script. $#ARGV is generally the number of
arguments minus one, because $ARGV[0] is the first
argument, not the program's command name itself. See $0
for the command name.
In other words, when @ARGV appears in scalar context it yields the
'size' of the @ARGV array, e.g.:
% cat foo.pl
printf(%d .. args = [%s]\n, int(@ARGV), join(', ', (@ARGV)));
% perl foo.pl
0 .. args = []
% perl foo.pl 1
1 .. args = [1]
% perl foo.pl 1 2 3
3 .. args = [1, 2, 3]
So when int(@ARGV) is zero you know that there are no arguments at all.
This means you can write your sh version like this in Perl:
#!/usr/bin/perl
if (int(@ARGV) == 0) {
die No args; at least one filename expected;
}
printf(%s\n, join(' ', (@ARGV)));
This is good enough as a command-line handling trick for really simple
scripts, but you should probably have a look at the Getopt::Std and the
Getopt::Long modules for longer scripts. Using them will make your
option parsing code much cleaner and easier to change in the future.
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Re: perl qstn...
Giorgos == Giorgos Keramidas keram...@ceid.upatras.gr writes:
Giorgos This means you can write your sh version like this in Perl:
Giorgos #!/usr/bin/perl
Giorgos if (int(@ARGV) == 0) {
Giorgos die No args; at least one filename expected;
Giorgos }
Giorgos printf(%s\n, join(' ', (@ARGV)));
Which, when you're not speaking Perl with a C accent, expressed more
natively as:
@ARGV or die No args: at least one filename expected;
print @ARGV\n;
--
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Smalltalk/Perl/Unix consulting, Technical writing, Comedy, etc. etc.
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Re: perl qstn...
Hi--
On Apr 6, 2010, at 6:21 AM, Randal L. Schwartz wrote:
RW == RW rwmailli...@googlemail.com writes:
RW Imperative languages have a natural order of decision followed by
RW action, and code is most easily readable if the syntax doesn't try to
RW subvert that.
And yet, there's an equally valid argument that the most important
thing should stand out the most. In that sense, in the Perl statement:
warn x = $x, y = $y, z = $z\n
if $debug;
... the most important part is that it's printing something to stderr,
and what's being printed. It's only minor that it's only when
debugging, and luckily Perl lets us relegate that to the tail end of
the statement.
Now, if you argue oh, the most important thing there is 'if debug',
then fine, you'd write that as:
if ($debug) { warn ... }
And I'd be fine with that.
Let's suppose you want to display one message if debugging is enabled, and a
shorter message if it is not. Adding an else clause to an if statement is a
natural change and the result remains highly readable. Can one even use this
postfix test syntax with an else, or would you have to re-write the first
version entirely?
As far as I am concerned, the first version resembles exception handling, ie:
try:
something
except Error1:
handle error
...and should be reserved for situations where the statement is expected to run
normally. If it is reasonable that the test might fail more often than in
unusual circumstances, then I'd really prefer to put the test first.
If you don't like all this freedom, there's always Python. :)
Yes, Perl lets you innovate a remarkable number of ways of solving the same
problem using syntax that varies from clean and maintainable to constructs
which even the original author won't understand without effort a few months
later. It seems to be uncommon for one to write unreadable Python code; I'm
not sure additional freedom to write obfuscated code would be as beneficial as
one may assume
Regards,
--
-Chuck
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Re: perl qstn...
Chuck == Chuck Swiger cswi...@mac.com writes: Chuck Let's suppose you want to display one message if debugging is Chuck enabled, and a shorter message if it is not. Then you wouldn't have used this construct. If you don't like all this freedom, there's always Python. :) Chuck Yes, Perl lets you innovate a remarkable number of ways of Chuck solving the same problem using syntax that varies from clean and Chuck maintainable to constructs which even the original author won't Chuck understand without effort a few months later. It seems to be Chuck uncommon for one to write unreadable Python code; I'm not sure Chuck additional freedom to write obfuscated code would be as Chuck beneficial as one may assume I call shenanigans: False dichotomy. Perl has *many* options that are all clear and readable, and some that aren't. Python has a *few* options that are all clear and readable, and some that aren't. You may not appreciate that freedom. Others do. With freedom comes responsibility. If that's not for you, Perl's not for you. -- Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095 mer...@stonehenge.com URL:http://www.stonehenge.com/merlyn/ Smalltalk/Perl/Unix consulting, Technical writing, Comedy, etc. etc. See http://methodsandmessages.vox.com/ for Smalltalk and Seaside discussion ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: perl qstn...
On Apr 6, 2010, at 11:07 AM, Randal L. Schwartz wrote: Chuck == Chuck Swiger cswi...@mac.com writes: Chuck Let's suppose you want to display one message if debugging is Chuck enabled, and a shorter message if it is not. Then you wouldn't have used this construct. If the construct isn't a good idea considering the most obvious change one might make to the code, I would conclude that it's probably never going to be a good idea to use such a thing. Surely Perl source code shouldn't be considered as write-once, modify-never? If you don't like all this freedom, there's always Python. :) Chuck Yes, Perl lets you innovate a remarkable number of ways of Chuck solving the same problem using syntax that varies from clean and Chuck maintainable to constructs which even the original author won't Chuck understand without effort a few months later. It seems to be Chuck uncommon for one to write unreadable Python code; I'm not sure Chuck additional freedom to write obfuscated code would be as Chuck beneficial as one may assume I call shenanigans: False dichotomy. I agree: the assertion you've made that Python lacks freedom is a false dichotomy. As we all know, any language which is adequately expressive can be used to write arbitrary code; much less languages which permit callouts or extension mechanisms to invoke native C/assembler/etc code. If you really find an advantage in obfuscated syntax and regard it as representing more freedom, I won't argue that opinion with you directly, but instead ask that you demonstrate that this supposed freedom results in better code, ease of maintainability, etc: Perl has *many* options that are all clear and readable, and some that aren't. Python has a *few* options that are all clear and readable, and some that aren't. ...and an example or two would be? You may not appreciate that freedom. Others do. With freedom comes responsibility. If that's not for you, Perl's not for you. I would suggest that good software not only allows the user the full freedom to do anything which is possible, it should also avoid asking the user about choices which are impossible/invalid/wrong/etc. This can be input field validation, middleware logic, this can be determining the present state and greying out options which are not currently applicable, etc. Regards, -- -Chuck ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: perl qstn...
Chuck == Chuck Swiger cswi...@mac.com writes: Then you wouldn't have used this construct. Chuck If the construct isn't a good idea considering the most obvious Chuck change one might make to the code, Objection: presumes facts not in evidence, your honor. Seriously, I've written thousands of lines that look like: print . if $flag; over the years (decades), and only *once* or *twice* do I ever recall saying oh, I actually wanted a two-way switch, and had to rewrite it. So most obvious to you is clearly not what is actually most likely. This undermines the rest of your argument, but let's read on... Chuck Surely Perl source code shouldn't be considered as write-once, Chuck modify-never? Yes, and that's also presumes facts not in evidence. See above. Chuck I would suggest that good software not only allows the user the Chuck full freedom to do anything which is possible, it should also Chuck avoid asking the user about choices which are Chuck impossible/invalid/wrong/etc. This can be input field Chuck validation, middleware logic, this can be determining the present Chuck state and greying out options which are not currently applicable, Chuck etc. I agree. The difference with Perl is that there are often many equally good ways to choose. If that's too much repsonsibility for you, please don't use Perl. -- Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095 mer...@stonehenge.com URL:http://www.stonehenge.com/merlyn/ Smalltalk/Perl/Unix consulting, Technical writing, Comedy, etc. etc. See http://methodsandmessages.vox.com/ for Smalltalk and Seaside discussion ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: perl qstn...
On Apr 6, 2010, at 11:43 AM, Randal L. Schwartz wrote: Chuck == Chuck Swiger cswi...@mac.com writes: Then you wouldn't have used this construct. Chuck If the construct isn't a good idea considering the most obvious Chuck change one might make to the code, Objection: presumes facts not in evidence, your honor. This isn't a court-room. I don't mind rhetorical flourishes, but if you are unwilling to consider how a statement might be changed over time as the circumstances require, even for the sake of discussion, well, in doing so you've chosen to not consider code maintainability. Seriously, I've written thousands of lines that look like: print . if $flag; over the years (decades), and only *once* or *twice* do I ever recall saying oh, I actually wanted a two-way switch, and had to rewrite it. So most obvious to you is clearly not what is actually most likely. Very well; I would like to hear you propose another type of change that might be made to this sort of postfix test syntax which you consider to be most likely. I find it remarkable, and nearly unbelievable, that one would only need to add an else clause to such a statement less often than 0.1% of the time. Frankly, I wouldn't mind taking a look through a few revisions of something you'd written (perhaps via CVSweb or similar) to see what kind of changes you do make to code over time. Chuck Surely Perl source code shouldn't be considered as write-once, Chuck modify-never? Yes, and that's also presumes facts not in evidence. See above. I'd be happy to take a look at your evidence. In fact, I'd already asked a similar question: Perl has *many* options that are all clear and readable, and some that aren't. Python has a *few* options that are all clear and readable, and some that aren't. ...and an example or two would be? ...and yet I do not see a response. Regards, -- -Chuck ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: perl qstn...
Chuck == Chuck Swiger cswi...@mac.com writes: Chuck Very well; I would like to hear you propose another type of Chuck change that might be made to this sort of postfix test syntax Chuck which you consider to be most likely. Maybe the content of the text message. I change that stuff all the time. Or maybe the exact nature of the condition. That also changes. Let me short cut the rest of the discussion, by summarizing: You and and I have different favorite languages However, our positions are different about the fact that we have different favorite languages. I'm perfectly willing to let you have Python, and work productively in it, while I'm happily being productive with Perl. I'm also perfectly willing to allow you imagine faults with Perl, even though after having used Perl productively for 20 years, those problems just don't arise in practice. You, on the other hand, seem to want to convince me that I couldn't have possibly been as productive in Perl as I have for the past 20 years, because of these alleged insurmountable problems. You seem to want to ensure that whatever my experience of Perl might be, that it is somehow wrong or tainted or misinformed. Hmm. Really? Really? Now, in the greater range of things, which position is more useful? Can we agree that we've gone *way beyond* the topic of freebsd-questions as well, and if anyone hasn't killfiled us already, they should have? :-) Now, on the other hand, emacs rules, vi sucks. :-) :-) -- Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095 mer...@stonehenge.com URL:http://www.stonehenge.com/merlyn/ Smalltalk/Perl/Unix consulting, Technical writing, Comedy, etc. etc. See http://methodsandmessages.vox.com/ for Smalltalk and Seaside discussion ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: perl qstn...
On 2010.04.06 17:10, Randal L. Schwartz wrote: Now, on the other hand, emacs rules, vi sucks. :-) :-) ok, ok. I was on the side of Perl, and was content following this thread, but now I don't like you anymore :P heh ;) Steve ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: perl qstn...
On Tue, Apr 06, 2010 at 06:17:41PM -0400, Steve Bertrand wrote: On 2010.04.06 17:10, Randal L. Schwartz wrote: Now, on the other hand, emacs rules, vi sucks. :-) :-) ok, ok. I was on the side of Perl, and was content following this thread, but now I don't like you anymore :P heh ;) Steve I'm willing to let the emacs users have their emacs, and to enjoy my vi. I guess the longer name (emacs) suits people who like pressing more buttons to accomplish the same amount of work anyway. -- Chad Perrin [ original content licensed OWL: http://owl.apotheon.org ] pgpwq7ywxcB58.pgp Description: PGP signature
Re: perl qstn...
On Tue, Apr 06, 2010 at 01:20:49PM +0100, RW wrote: On Mon, 5 Apr 2010 19:55:44 -0600 Chad Perrin per...@apotheon.com wrote: On Mon, Apr 05, 2010 at 05:36:32PM +0100, RW wrote: IMO this is a bad mistake that other languages were quite right not to copy - a test shouldn't come after a block of code unless it's evaluated after the block (as in repeat...until) There are more things in heav'n and earth, Horatio, than are dreamt of by designers of eagerly evaluated prefix notation languages. And most of them are obscure for good reasons. Just because a a syntax fits into a classification scheme doesn't make it a good idea. The fact something is popular doesn't mean it's a good idea. Shall we trade more trite sniping, or would you like to say something more substantive? In no way, and at no time, did I imply that using unless like an infix operator is a good idea just because it fits with a given syntax classification. Natural languages are mostly driven by spoken usage, in which people firm-up half-formed ideas as they speak - this is not a good model for programming languages. If you are hacking out a quick and dirty script it may be convenient to type the decision after the action, but it don't I think it promotes good quality software. This sounds exactly like the complaints Pythonistas use to explain why they have a deep hatred of Perl. If that's how you feel, I'd prefer you stop trying to tell me how Perl should work, and just use something else. Imperative languages have a natural order of decision followed by action, and code is most easily readable if the syntax doesn't try to subvert that. . . . except when the natural order of decision varies significantly, such as when comparing functions with operators. It gets even more confusing when both functions and operators are actually methods in object oriented languages with an imperative design, because suddenly the difference between a function and an operator becomes purely arbitrary. There's nothing about arbitrariness that suggests a natural order. It's kind of odd you rail against natural language then talk about imperative languages having a natural order -- which is, presumably, based on the expectations of people who have been conditioned to think that way by their use of natural language. Frankly, if everybody just stuck to a purely natural order of decision approach to imperative language design, we would never even have developed structured programming. -- Chad Perrin [ original content licensed OWL: http://owl.apotheon.org ] pgpEUjI65NlvI.pgp Description: PGP signature
Re: perl qstn...
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On 04/04/2010 19:48:14, Alejandro Imass wrote:
But honestly pun aside unless(){} is far more readable than if(!){}
and _especially_ if you are programming in an exception manner as you
correctly point out. Every language should have an unless construct.
I've always found that 'unless' makes a great deal of sense when used
in the alternate syntax:
do_foo()
unless $condition ;
As far as I know, perl and its descendant ruby are the only programming
languages that let you put the condition test after the action, despite
this being exceeding familiar in human languages.
Cheers,
Matthew
- --
Dr Matthew J Seaman MA, D.Phil. 7 Priory Courtyard
Flat 3
PGP: http://www.infracaninophile.co.uk/pgpkey Ramsgate
Kent, CT11 9PW
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Re: perl qstn...
Matthew == Matthew Seaman m.sea...@infracaninophile.co.uk writes: Matthew As far as I know, perl and its descendant ruby are the only Matthew programming languages that let you put the condition test after Matthew the action, despite this being exceeding familiar in human Matthew languages. Except, we old-timers remember that Larry Wall directly lifted this from RSTS-E BASIC-PLUS, which he had used at Pacific University as a student. Having hacked BASIC-PLUS myself around the same time, I recognized it instantly. BASIC-PLUS went further though, allowing them to be nested. So you'd end up with monstrosities like: PRINT a IF a % 3 = 2 FOR a = b TO b+7 FOR b = 0 TO 90 STEP 10; Thankfully, Larry limited Perl's statement modifiers to precisely one level. :) Just another old geezer, -- Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095 mer...@stonehenge.com URL:http://www.stonehenge.com/merlyn/ Smalltalk/Perl/Unix consulting, Technical writing, Comedy, etc. etc. See http://methodsandmessages.vox.com/ for Smalltalk and Seaside discussion ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: perl qstn...
in message 867homm1qf@red.stonehenge.com, wrote Randal L. Schwartz thusly... Matthew == Matthew Seaman m.sea...@infracaninophile.co.uk writes: Matthew As far as I know, perl and its descendant ruby are the Matthew only programming languages that let you put the Matthew condition test after the action, despite this being Matthew exceeding familiar in human languages. Except, we old-timers remember that Larry Wall directly lifted this from RSTS-E BASIC-PLUS, which he had used at Pacific University as a student. Having hacked BASIC-PLUS myself around the same time, I recognized it instantly. BASIC-PLUS went further though, allowing them to be nested. So you'd end up with monstrosities like: Beauty is in the eye ..., or, perhaos you would prefer Only a mother would PRINT a IF a % 3 = 2 FOR a = b TO b+7 FOR b = 0 TO 90 STEP 10; Oh Randal, don't tease me please about the lack of such loveliness in perl. - parv -- ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: perl qstn...
On Mon, 05 Apr 2010 09:57:17 +0100 Matthew Seaman m.sea...@infracaninophile.co.uk wrote: -BEGIN PGP SIGNED MESSAGE- Hash: SHA1 I've always found that 'unless' makes a great deal of sense when used in the alternate syntax: do_foo() unless $condition ; As far as I know, perl and its descendant ruby are the only programming languages that let you put the condition test after the action, IMO this is a bad mistake that other languages were quite right not to copy - a test shouldn't come after a block of code unless it's evaluated after the block (as in repeat...until) ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: perl qstn...
On Mon, Apr 05, 2010 at 05:36:32PM +0100, RW wrote: IMO this is a bad mistake that other languages were quite right not to copy - a test shouldn't come after a block of code unless it's evaluated after the block (as in repeat...until) There are more things in heav'n and earth, Horatio, than are dreamt of by designers of eagerly evaluated prefix notation languages. Actually, I'd think that using unless that way would be right up the alley of the users of most programming languages, since unless is here just being used the same way as an infix notation operator with very high precedence. If you want to get rigorous about it, I'd prefer this approach: unless (condition) (result) . . . where it uses strict prefix notation. I know that some people think postfix notation is the bee's knees because of implementation reasons, but frankly, implementation should be something we never have to see, in my opinion -- unless we're actually implementing it. Computers are for scut work; humans are for idea work. Failing strict prefix notation, I'm okay with the way Perl and Ruby use unless. This: (result) unless (condition) . . . could be explained away as fitting with any of: 1. conforming to natural language expectations, thus leaving implementation scut-work to the realm of the computer 2. infix notation with very high precedence for unless 3. lazy evaluation, where the (result) is not evaluated until it is needed, which gives the interpreter plenty of time to notice there's an unless immediately following it Obviously, the real answer in the case of Ruby and Perl falls somewhere around 1.5, but 3 is still a believable-sounding excuse, and perfectly acceptable to me. -- Chad Perrin [ original content licensed OWL: http://owl.apotheon.org ] pgpKFRwk4tO9r.pgp Description: PGP signature
Re: perl qstn...
On Sun, 2010-04-04 at 00:07 -0400, Greg Larkin wrote:
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Gary Kline wrote:
guys,
i'm finally trying to get my private scripts and binaries in
~/bin in order. several of my perl scripts were meant to be
throwaway ... but a few seem to be more useful and i would have
to have informational or usage{} type messages.
if a .pl script has to have at least one arg, is there an easy
way to do that? can i have a perl fn called usage() that would
be fed various strings?
tia,
gary
Hi Gary,
Check out this Perl module that builds on Getopt::Long, but also
includes support for echoing usage messages for each option:
http://search.cpan.org/~rjbs/Getopt-Long-Descriptive-0.085/lib/Getopt/Long/Descriptive.pm
Hope that helps,
Greg
thanks for your url as well and the others to posted. but it seems like
overkill since i dont need any explicit option or argument. i just need
the script to tell me whether i have an arg or not. following is
something i've kept in one of my junk drawers from when i was learning
to write bourne sscripts. it uses the $[token] syntax that determines
whether there are Any args on the cmdline. if not, the script prints a
message and exits.
#!/bin/sh
if [ $# -eq 0 ]
then
echo No args; need filename.
else
echo $1
fi
After a couple hours experimentation, the following does the same for my
perl scripts:
#!/usr/bin/perl
$argc = @ARGV;
if (! $argc ) {
printf(No args; need filename.\n);
}
else {
printf(%s\n, @ARGV);
}
gary
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Re: perl qstn...
Gary == Gary Kline kl...@thought.org writes:
Gary #!/usr/bin/perl
Gary $argc = @ARGV;
Gary if (! $argc ) {
Gary printf(No args; need filename.\n);
Gary }
Gary else {
Gary printf(%s\n, @ARGV);
Gary }
Even simpler:
if (@ARGV) {
print No args\n;
} else {
print arg is $ARGV[0]\n;
}
If you're studying perl, you might want to join the very
beginner-friendly mailing list, info at
http://lists.perl.org/list/beginners.html, or start a conversation on
perlmonks.org, also relatively beginner-friendly.
And I'd recommend a couple of good books, but I might be seen as
self-pimping. :)
But if you look at http://learn.perl.org/ you'll see a number of other
resources, including free tutorials online.
print Just another Perl hacker,; # the original
--
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mer...@stonehenge.com URL:http://www.stonehenge.com/merlyn/
Smalltalk/Perl/Unix consulting, Technical writing, Comedy, etc. etc.
See http://methodsandmessages.vox.com/ for Smalltalk and Seaside discussion
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Re: perl qstn...
Randal == Randal L Schwartz mer...@stonehenge.com writes:
Randal Even simpler:
Randal if (@ARGV) {
Randal print No args\n;
Randal } else {
Randal print arg is $ARGV[0]\n;
Randal }
Augh. I hit send just as I realized that's backwards. Need
more caffiene. Swap the true and false blocks there. :)
--
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mer...@stonehenge.com URL:http://www.stonehenge.com/merlyn/
Smalltalk/Perl/Unix consulting, Technical writing, Comedy, etc. etc.
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Re: perl qstn...
On Sun, Apr 04, 2010 at 08:25:03AM -0700, Randal L. Schwartz wrote:
Even simpler:
if (@ARGV) {
print No args\n;
} else {
print arg is $ARGV[0]\n;
}
As Randal noted, he accidentally swapped the conditions here. Just for
the sake of absolute clarity, I'll actually swap them:
if (@ARGV) {
print arg is $ARGV[0]\n;
} else {
print no args\n;
}
If you're studying perl, you might want to join the very
beginner-friendly mailing list, info at
http://lists.perl.org/list/beginners.html, or start a conversation on
perlmonks.org, also relatively beginner-friendly.
PerlMonks in particular is an excellent resource. I haven't been active
there recently, but when I have been active there, I've always found it
rewarding and educational. I can't recommend it enough.
And I'd recommend a couple of good books, but I might be seen as
self-pimping. :)
That's okay. I'll pimp them for you.
Learning Perl, also known as The Llama Book (because it has a llama on
the cover), is one of the all-time best beginner's books for *any*
language that I've ever encountered. I've gone through both the second
and fourth editions, and both are excellent books. I prefer the
organization of the second edition a bit, but the fourth is a trifle more
up to date and does a much better job of covering Windows-related Perl
development issues. If you're only worried about Unixy development and
execution environments, my personal recommendation would be the second
edition, though I suppose your mileage may vary.
As a follow-up to the Llama, the Alpaca book (it has an alpaca on the
cover, naturally) -- in its first edition known as Learning Perl Objects,
References, and Modules (or Perl PORM, as I like to call it), and in
later editions titled Intermediate Perl -- is also an excellent book. In
addition to teaching more about Perl in particular, it also teaches some
important general programming concepts from a Perl perspective, thus
helping broaden your understanding of programming in general.
The final member of the traditional camelid trilogy, and a great book to
tack onto the list after the Alpaca, is the Camel Book, titled
Programming Perl. It's sorta the definitive reference for Perl
programmers, and covers a lot more of the language and its philosophy
than the Llama and Alpaca, though in my opinion the Llama and Alpaca
together provide a needed introduction that the Camel only skims past
(out of necessity, really, since a hand-holding introduction isn't really
the book's purpose).
There's also Mastering Perl, which was written as a sequel to
Intermediate Perl, and I'm sure it's an excellent book. I haven't read
it, though, and know next to nothing about it, so I can't really
recommend it.
All four of the above are published by O'Reilly, and the three I've read
at least are each the kind of book that has given O'Reilly its reputation
as a purveyor of excellent technical books. Perl is blessed by an absurd
number of excellent programming books by knowledgeable authors, and there
are many more that are worth your time as well -- but in general the
above are the canonical starting steps, with others following from there
as you start figuring out what specific areas you want to give your focus
next. Unfortunately, there are also a number of really crappy Perl books
out there (many books that spell it PERL, in all-capital letters, are
among the not-so-great books), and as such I figured I should be explicit
in sharing my thoughts on the best books to get started in Perl.
Now that I've gotten so far off-topic for this list, I'll return you to
your regularly scheduled programming.
But if you look at http://learn.perl.org/ you'll see a number of other
resources, including free tutorials online.
print Just another Perl hacker,; # the original
--
Chad Perrin [ original content licensed OWL: http://owl.apotheon.org ]
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Re: perl qstn...
On Sun, Apr 4, 2010 at 11:27 AM, Randal L. Schwartz
mer...@stonehenge.com wrote:
Randal == Randal L Schwartz mer...@stonehenge.com writes:
Randal Even simpler:
Randal if (@ARGV) {
did you mean unless? ;-)
Randal print No args\n;
Randal } else {
Randal print arg is $ARGV[0]\n;
Randal }
Augh. I hit send just as I realized that's backwards. Need
more caffiene. Swap the true and false blocks there. :)
--
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mer...@stonehenge.com URL:http://www.stonehenge.com/merlyn/
Smalltalk/Perl/Unix consulting, Technical writing, Comedy, etc. etc.
See http://methodsandmessages.vox.com/ for Smalltalk and Seaside discussion
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Re: perl qstn...
On Sun, Apr 04, 2010 at 12:45:30PM -0400, Alejandro Imass wrote:
On Sun, Apr 4, 2010 at 11:27 AM, Randal L. Schwartz
mer...@stonehenge.com wrote:
Randal == Randal L Schwartz mer...@stonehenge.com writes:
Randal Even simpler:
Randal if (@ARGV) {
did you mean unless? ;-)
I find if to be clearer than unless when there's an else, so
instead of making that if into an unless, I'd just swap the
conditional actions.
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Re: perl qstn...
On Sun, Apr 4, 2010 at 11:04 AM, Chad Perrin per...@apotheon.com wrote: On Sun, Apr 04, 2010 at 08:25:03AM -0700, Randal L. Schwartz wrote: [...] The final member of the traditional camelid trilogy, and a great book to Hmm, so there _are_ in fact several trilogies! g I would swap the Camel for the Black Leopard anyday. Not implying that the author is not a great writer, but the Camel book is mostly a printout of perldoc perl g sure hope Larry is not on this list lol tack onto the list after the Alpaca, is the Camel Book, titled Programming Perl. It's sorta the definitive reference for Perl programmers, and covers a lot more of the language and its philosophy than the Llama and Alpaca, though in my opinion the Llama and Alpaca together provide a needed introduction that the Camel only skims past (out of necessity, really, since a hand-holding introduction isn't really the book's purpose). There's also Mastering Perl, which was written as a sequel to Intermediate Perl, and I'm sure it's an excellent book. I haven't read it, though, and know next to nothing about it, so I can't really recommend it. Perhaps the Vicuña and kids is in fact the thrid member of the trilogy, but the Black Leopard is a must have to become a respected Perl hacker IMHO. Anyway, since this is all OT I started this thread in PM for your comments: http://www.perlmonks.org/?node_id=832725 Cheers, Alejandro Imass ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: perl qstn...
On Sun, 4 Apr 2010 10:33:53 -0600, Chad Perrin per...@apotheon.com wrote:
On Sun, Apr 04, 2010 at 12:45:30PM -0400, Alejandro Imass wrote:
did you mean unless? ;-)
I find if to be clearer than unless when there's an else, so
instead of making that if into an unless, I'd just swap the
conditional actions.
A quite language-independent technical sidenote :-) ...
If your if() conditional is to test an exception, something
that you usually DON'T want to happen - i. e. missing command
line parameters - you can use the ! negation operator to
indicate this in the if() argument.
if(!...@argv) {
print No args\n;
exit;
}
In a short error message, you should indicate what you are
expecting, e. g. with a synopsis or a simple example (no
need for a 25 line help text here, e. g.
print Input file name is missing.\n;
print usage: blabla.pl filename\n;
or
print Use: blabla.pl inputfile\n;
And you could even force perl to exit with an exit code != 0
to indicate that something happened (e. g. program wasn't run
successfully).
Now, as the don't want case has been considered, you can
easily continue with your program, no need to put it into
an else { } branch.
PS. I'm not familiar with perl enough to be sure that the !
operator can be used at @ARGV to make sure it's 0,
and how or if to use exit() to set the return code.
I hardly can read perl at all, so the essence of my
examples is of a rather generic nature. :-)
--
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Magdeburg, Germany
Happy FreeBSD user since 4.0
Andra moi ennepe, Mousa, ...
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Re: perl qstn...
On Sun, Apr 4, 2010 at 2:14 PM, Polytropon free...@edvax.de wrote:
On Sun, 4 Apr 2010 10:33:53 -0600, Chad Perrin per...@apotheon.com wrote:
On Sun, Apr 04, 2010 at 12:45:30PM -0400, Alejandro Imass wrote:
did you mean unless? ;-)
I find if to be clearer than unless when there's an else, so
instead of making that if into an unless, I'd just swap the
conditional actions.
A quite language-independent technical sidenote :-) ...
grin
If your if() conditional is to test an exception, something
that you usually DON'T want to happen - i. e. missing command
line parameters - you can use the ! negation operator to
indicate this in the if() argument.
_precisely_ what unless is for. it's just a funny way of writing
if(!... or should I say if(! is a funny way to write unless ;-)
But honestly pun aside unless(){} is far more readable than if(!){}
and _especially_ if you are programming in an exception manner as you
correctly point out. Every language should have an unless construct.
[...]
And you could even force perl to exit with an exit code != 0
to indicate that something happened (e. g. program wasn't run
successfully).
a good practice in any language...
Now, as the don't want case has been considered, you can
easily continue with your program, no need to put it into
an else { } branch.
ahh! the clarity of unless
PS. I'm not familiar with perl enough to be sure that the !
operator can be used at @ARGV to make sure it's 0,
In scalar context will automagically return the number of elements
perldoc perlintro (section Perl variable types)
and how or if to use exit() to set the return code.
die Bailing cause you forgot the filename unless @ARGV
Yes, that _is_ actual code :) Will not only die with a pretty message
on STDERR but will return the value of $! (errno) as exit value. (no
need to make up exit codes) Good thing we are on a FBSD list, because
I can't see the sense of programming in a non-nix environment ;-)
I hardly can read perl at all, so the essence of my
examples is of a rather generic nature. :-)
Look mommi! Reading Perl is just like reading plain english! (or in
Nigerian spam for that matter
http://search.cpan.org/~jwalt/Acme-Lingua-NIGERIAN-1.0.0/NIGERIAN.pm)
Cheers,
Alejandro Imass
--
Polytropon
Magdeburg, Germany
Happy FreeBSD user since 4.0
Andra moi ennepe, Mousa, ...
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Re: perl qstn...
On Sun, Apr 4, 2010 at 11:25 AM, Randal L. Schwartz mer...@stonehenge.com wrote: Gary == Gary Kline kl...@thought.org writes: [...] And I'd recommend a couple of good books, but I might be seen as self-pimping. :) But if you look at http://learn.perl.org/ you'll see a number of other resources, including free tutorials online. The trilogy is a must-have regardless if you are beginner intermediate or advanced, and regardless of who wrote them ;-) - Learning Perl - Intermediate Perl - Advanced Perl Programming Of course, the Camel book (Programming Perl), and Perl Best Practices which IMHO is a must read for _any_ language but especially for Perl hackers. More here: http://oreilly.com/pub/topic/perl Best, Alejandro Imass print Just another Perl hacker,; # the original -- Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095 mer...@stonehenge.com URL:http://www.stonehenge.com/merlyn/ Smalltalk/Perl/Unix consulting, Technical writing, Comedy, etc. etc. See http://methodsandmessages.vox.com/ for Smalltalk and Seaside discussion ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: perl qstn...
On Sun, Apr 04, 2010 at 08:25:03AM -0700, Randal L. Schwartz wrote:
Gary == Gary Kline kl...@thought.org writes:
Gary #!/usr/bin/perl
Gary $argc = @ARGV;
Gary if (! $argc ) {
Gary printf(No args; need filename.\n);
Gary }
Gary else {
Gary printf(%s\n, @ARGV);
Gary }
Even simpler:
if (@ARGV) {
print No args\n;
} else {
print arg is $ARGV[0]\n;
}
If you're studying perl, you might want to join the very
beginner-friendly mailing list, info at
http://lists.perl.org/list/beginners.html, or start a conversation on
perlmonks.org, also relatively beginner-friendly.
And I'd recommend a couple of good books, but I might be seen as
self-pimping. :)
hey man, pimp away! we'll all learn a few tricks. ---i had
to teach myself perl around '96 and bought a couple books,
one with a floppy full of short programs. After doing a
find . -name * -exec head -15 {} \; | more thru the
truckload of these nifties, i finally came across the $argc
idea.
there are around a dozen no-longer-throwaways that need the
kind of no-arg tip just to make the scripts more user
friendly. even tho i'm the Only person who'll ever use them.
---Maybe you can clue me in on this one: around a dozen years
ago i somw found a recursive grep named tgrep online. to save
tying, i renamed it rgr. i can start anywhere and 'rgr pattern'
--WITHOUT ANY ASTERISK-- will find any pattern and skip
binary or tarballs or compressed files. given this, rgr has
become my favorite utility, but since it doesn't have All of grep's
options, yes, it's tru e, there are times whrn i have to use
the real thing. i have searched for tgrep and cannot find a
newer more complete version. would you or anyone reading
this know where an upgraded version is?
Here is the Usage string:
p4 13:07 tao [5524] rgr
Usage: tgrep [-iredblLnf] regexp filepat ...
tgrep -h for help
if not for trgep/rgr my shoulder would've fallen off and just
laid on the floor; that's how much i use this script. having
the 'w' switch would be nice, so would the -N switch.
But if you look at http://learn.perl.org/ you'll see a number of other
resources, including free tutorials online.
tx for the pointer; i'll add it to my bookmarks.
gary
print Just another Perl hacker,; # the original
--
Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095
mer...@stonehenge.com URL:http://www.stonehenge.com/merlyn/
Smalltalk/Perl/Unix consulting, Technical writing, Comedy, etc. etc.
See http://methodsandmessages.vox.com/ for Smalltalk and Seaside discussion
--
Gary Kline kl...@thought.org http://www.thought.org Public Service Unix
http://jottings.thought.org http://transfinite.thought.org
The 7.79a release of Jottings: http://jottings.thought.org/index.php
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Re: perl qstn...
in message 20100404203951.gb47...@thought.org, wrote Gary Kline thusly... ---Maybe you can clue me in on this one: around a dozen years ago i somw found a recursive grep named tgrep online. to save tying, i renamed it rgr. i can start anywhere and 'rgr pattern' --WITHOUT ANY ASTERISK-- will find any pattern and skip binary or tarballs or compressed files. given this, rgr has become my favorite utility, but since it doesn't have All of grep's options, yes, it's tru e, there are times whrn i have to use the real thing. i have searched for tgrep and cannot find a newer more complete version. would you or anyone reading this know where an upgraded version is? Here is the Usage string: p4 13:07 tao [5524] rgr Usage: tgrep [-iredblLnf] regexp filepat ... tgrep -h for help if not for trgep/rgr my shoulder would've fallen off and just laid on the floor; that's how much i use this script. having the 'w' switch would be nice, so would the -N switch. What does -N do in grep included with FreeBSD? My version (FreeBSD 8) only has -n. I know of one tcgrep (by Tom Christiansen) ... http://www.perl.com/CPAN/authors/id/TOMC/scripts/tcgrep.gz Then, there is ack ... http://search.cpan.org/dist/ack/ack ... may need to tinker with option to search non-Perl files (see -a option). Or, simply ... #!/bin/sh # If your particular egrep is laced with potent PCRE, may use -P # option (before $@) to specify Perl regex. egrep -r $@ . - parv -- ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Caution:: Off-topic Re: perl qstn...
On Sun, Apr 04, 2010 at 12:45:30PM -0400, Alejandro Imass wrote:
On Sun, Apr 4, 2010 at 11:27 AM, Randal L. Schwartz
mer...@stonehenge.com wrote:
Randal == Randal L Schwartz mer...@stonehenge.com writes:
Randal Even simpler:
Randal if (@ARGV) {
did you mean unless? ;-)
Randal print No args\n;
Randal } else {
Randal print arg is $ARGV[0]\n;
Randal }
Augh. I hit send just as I realized that's backwards. Need
more caffiene. Swap the true and false blocks there. :)
just having my 77th mug of french roast, so i'm hip.
...Anyway, here's one i'v been wanting to ask for years but
don't know where to pose. Is C dead? i mean, since it's
been official for years, can C add things like the unless
keyword? Can C include the perl regex packages?
if i asked this anywhere else, they would send out the men in
white coats an d haul me away. here i'm safe:)
anybody know if we need a new C [[maybe D]] that would be
allowed to grow?
gary
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mer...@stonehenge.com URL:http://www.stonehenge.com/merlyn/
Smalltalk/Perl/Unix consulting, Technical writing, Comedy, etc. etc.
See http://methodsandmessages.vox.com/ for Smalltalk and Seaside discussion
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Gary Kline kl...@thought.org http://www.thought.org Public Service Unix
http://jottings.thought.org http://transfinite.thought.org
The 7.79a release of Jottings: http://jottings.thought.org/index.php
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Re: perl qstn...
On Sun, Apr 04, 2010 at 10:58:35AM -1000, p...@pair.com wrote: in message 20100404203951.gb47...@thought.org, wrote Gary Kline thusly... ---Maybe you can clue me in on this one: around a dozen years ago i somw found a recursive grep named tgrep online. to save tying, i renamed it rgr. i can start anywhere and 'rgr pattern' --WITHOUT ANY ASTERISK-- will find any pattern and skip binary or tarballs or compressed files. given this, rgr has become my favorite utility, but since it doesn't have All of grep's options, yes, it's tru e, there are times whrn i have to use the real thing. i have searched for tgrep and cannot find a newer more complete version. would you or anyone reading this know where an upgraded version is? Here is the Usage string: p4 13:07 tao [5524] rgr Usage: tgrep [-iredblLnf] regexp filepat ... tgrep -h for help if not for trgep/rgr my shoulder would've fallen off and just laid on the floor; that's how much i use this script. having the 'w' switch would be nice, so would the -N switch. What does -N do in grep included with FreeBSD? My version (FreeBSD 8) only has -n. Sorry, my bad. I should have said that N was any positive integer. Sometimes I'll be searching for a phrase that i'm not certain of and will type grep -7 PATTERN file[s] where PATTERN is a known. I'll pipe around for various other strings. I know of one tcgrep (by Tom Christiansen) ... http://www.perl.com/CPAN/authors/id/TOMC/scripts/tcgrep.gz Then, there is ack ... http://search.cpan.org/dist/ack/ack ... may need to tinker with option to search non-Perl files (see -a option). Or, simply ... #!/bin/sh # If your particular egrep is laced with potent PCRE, may use -P # option (before $@) to specify Perl regex. egrep -r $@ . this tgrep is from the NL; by a Prof Piet van Oostrum and is dated 5/19/93. i think ii wrote this fellow many years ago. Zip. I'll ck out ack when i'm using a gui mailer, thanks. gary - parv -- -- Gary Kline kl...@thought.org http://www.thought.org Public Service Unix http://jottings.thought.org http://transfinite.thought.org The 7.79a release of Jottings: http://jottings.thought.org/index.php ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: Caution:: Off-topic Re: perl qstn...
On Sun, Apr 4, 2010 at 11:33 PM, Gary Kline kl...@thought.org wrote: Can C include the perl regex packages? Yes! Just use PCRE. Or, if you prefer C++, Boost.Regex: http://www.pcre.org/ http://www.boost.org/doc/libs/1_42_0/libs/regex/doc/html/index.html -- Cordula's Web. http://www.cordula.ws/ ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: perl qstn...
From owner-freebsd-questi...@freebsd.org Sun Apr 4 17:14:17 2010 Date: Sun, 4 Apr 2010 15:13:49 -0700 From: Gary Kline kl...@thought.org To: Randal L. Schwartz mer...@stonehenge.com, glar...@freebsd.org, FreeBSD Mailing List freebsd-questions@freebsd.org Cc: Subject: Re: perl qstn... On Sun, Apr 04, 2010 at 10:58:35AM -1000, p...@pair.com wrote: in message 20100404203951.gb47...@thought.org, wrote Gary Kline thusly... ---Maybe you can clue me in on this one: around a dozen years ago i somw found a recursive grep named tgrep online. to save tying, i renamed it rgr. i can start anywhere and 'rgr pattern' --WITHOUT ANY ASTERISK-- will find any pattern and skip binary or tarballs or compressed files. given this, rgr has become my favorite utility, but since it doesn't have All of grep's options, yes, it's tru e, there are times whrn i have to use the real thing. i have searched for tgrep and cannot find a newer more complete version. would you or anyone reading this know where an upgraded version is? Here is the Usage string: p4 13:07 tao [5524] rgr Usage: tgrep [-iredblLnf] regexp filepat ... tgrep -h for help if not for trgep/rgr my shoulder would've fallen off and just laid on the floor; that's how much i use this script. having the 'w' switch would be nice, so would the -N switch. What does -N do in grep included with FreeBSD? My version (FreeBSD 8) only has -n. Sorry, my bad. I should have said that N was any positive integer. Sometimes I'll be searching for a phrase that i'm not certain of and will type grep -7 PATTERN file[s] where PATTERN is a known. I'll pipe around for various other strings. I know of one tcgrep (by Tom Christiansen) ... http://www.perl.com/CPAN/authors/id/TOMC/scripts/tcgrep.gz Then, there is ack ... http://search.cpan.org/dist/ack/ack ... may need to tinker with option to search non-Perl files (see -a option). Or, simply ... #!/bin/sh # If your particular egrep is laced with potent PCRE, may use -P # option (before $@) to specify Perl regex. egrep -r $@ . this tgrep is from the NL; by a Prof Piet van Oostrum and is dated 5/19/93. i think ii wrote this fellow many years ago. Zip. I'll ck out ack when i'm using a gui mailer, thanks. Google to the rescue. Given the program name, and the author, one finds that this code was in UNIX Power Tools (O'Reilly * Assoc.) ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: Caution:: Off-topic Re: perl qstn...
On Sun, Apr 04, 2010 at 02:33:02PM -0700, Gary Kline wrote: anybody know if we need a new C [[maybe D]] that would be allowed to grow? There's already a D. I don't really know much about it, though. -- Chad Perrin [ original content licensed OWL: http://owl.apotheon.org ] pgpluEACy1sZx.pgp Description: PGP signature
Re: perl qstn...
On Sun, Apr 04, 2010 at 08:14:21PM -0500, Robert Bonomi wrote: From owner-freebsd-questi...@freebsd.org Sun Apr 4 17:14:17 2010 Date: Sun, 4 Apr 2010 15:13:49 -0700 From: Gary Kline kl...@thought.org To: Randal L. Schwartz mer...@stonehenge.com, glar...@freebsd.org, FreeBSD Mailing List freebsd-questions@freebsd.org Cc: Subject: Re: perl qstn... On Sun, Apr 04, 2010 at 10:58:35AM -1000, p...@pair.com wrote: in message 20100404203951.gb47...@thought.org, wrote Gary Kline thusly... ---Maybe you can clue me in on this one: around a dozen years ago i somw found a recursive grep named tgrep online. to save tying, i renamed it rgr. i can start anywhere and 'rgr pattern' --WITHOUT ANY ASTERISK-- will find any pattern and skip binary or tarballs or compressed files. given this, rgr has become my favorite utility, but since it doesn't have All of grep's options, yes, it's tru e, there are times whrn i have to use the real thing. i have searched for tgrep and cannot find a newer more complete version. would you or anyone reading this know where an upgraded version is? Here is the Usage string: p4 13:07 tao [5524] rgr Usage: tgrep [-iredblLnf] regexp filepat ... tgrep -h for help [[ ... ]] Google to the rescue. Given the program name, and the author, one finds that this code was in UNIX Power Tools (O'Reilly * Assoc.) right; i've got the power tools book front and center. it must have come with tgrep on a floppy. -- Gary Kline kl...@thought.org http://www.thought.org Public Service Unix http://jottings.thought.org http://transfinite.thought.org The 7.79a release of Jottings: http://jottings.thought.org/index.php ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: perl qstn...
Gary == Gary Kline kl...@thought.org writes: Gary if a .pl script has to have at least one arg, is there an easy Gary way to do that? Dare I say, there's more than one way to do it? :) See the Getopt:: family in the CPAN. My favorite is Getopt::Long. -- Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095 mer...@stonehenge.com URL:http://www.stonehenge.com/merlyn/ Smalltalk/Perl/Unix consulting, Technical writing, Comedy, etc. etc. See http://methodsandmessages.vox.com/ for Smalltalk and Seaside discussion ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: perl qstn...
On Sat, Apr 03, 2010 at 02:17:06PM -0700, Randal L. Schwartz wrote: Gary == Gary Kline kl...@thought.org writes: Gary if a .pl script has to have at least one arg, is there an easy Gary way to do that? Dare I say, there's more than one way to do it? :) See the Getopt:: family in the CPAN. My favorite is Getopt::Long. For simple scripts I tend to use Getopt::Std instead, but Getopt::Long is great too. These two are pretty much the standard for command line option handling and help message generation in Perl. -- Chad Perrin [ original content licensed OWL: http://owl.apotheon.org ] pgpwV1YQ4xsBV.pgp Description: PGP signature
Re: perl qstn...
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Gary Kline wrote:
guys,
i'm finally trying to get my private scripts and binaries in
~/bin in order. several of my perl scripts were meant to be
throwaway ... but a few seem to be more useful and i would have
to have informational or usage{} type messages.
if a .pl script has to have at least one arg, is there an easy
way to do that? can i have a perl fn called usage() that would
be fed various strings?
tia,
gary
Hi Gary,
Check out this Perl module that builds on Getopt::Long, but also
includes support for echoing usage messages for each option:
http://search.cpan.org/~rjbs/Getopt-Long-Descriptive-0.085/lib/Getopt/Long/Descriptive.pm
Hope that helps,
Greg
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