Re: Cool/useful short examples of Perl?
On 30 May 2011 11:40, Leo Lapworth wrote:
I'm working on http://learn.perl.org/ and I'd like to have a few rotating
example of what can be done with Perl on the home page.
# see also perlvar: $BASETIME
{ my $t0 = time; sub elapsed { time - $t0 } }
--
Ruud
Re: Cool/useful short examples of Perl?
On 8 Jun 2011, at 13:17, Tom Hukins wrote:
> On Wed, Jun 08, 2011 at 02:00:41PM +0200, Abigail wrote:
>> I'd rather go for sacking people that don't know the difference
>> between
>>
>>if (something) { ... }
>>
>> and
>>
>>unless (!something) { ... }
>
> It's sunny outside and pubs are open: I can think of worse times to
> lose my job.
>
>> Or does everyone think they are always equivalent?
>
> I'm not everyone, and with a language as flexible as Perl I hesitate
> to make strong statements involving words like "always", but I don't
> recall encountering a situation where they differ.
If 'something' is 'something && something_else' then you *really* want to put
brackets around it before adding a '!' at the start.
But that's so trivial it barely needs saying, yes?
--
David Matthewman
Re: Cool/useful short examples of Perl?
On Wed, Jun 8, 2011 at 15:37, Matt Lawrence wrote: > Perl's canonical true and false are 1 and '' respectively Is that so? How would one find that out? Dump-ing 4==4 and 4==5 with Devel::Peek implies to me that true and false are PVNVs with integer, floating-point, and string values filled simultaneously, so I'm not sure how any of the three fields could be considered "the" value of those, er, values(?). Cheers, Philip -- Philip Newton
RE: Cool/useful short examples of Perl?
Apologies for including the top half of the digest. Chris
Re: Someone needs to take jwz aside...
David Cantrell wrote: It's the lack of a CPAN-a-like for any other language that keeps me coming back to perl. Of course, it's possible that the Comprehensive Python Archive Network or similar for ruby/javascript/java/C/whatever does exist but I just can't find it. But then, if I can't find it, it's not much use. http://npmjs.org/ I'm actually liking it more than CPAN for publishing and installing stuff. The only weak area is lack of search.cpan.org. Note that this is for Node.js stuff only - not Javascript in general. __ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email __
Re: Someone needs to take jwz aside...
Hakim Cassimally wrote: While Javascript-the-language is lovely (as you say, better in some respects, worse in others, than Perl), that's only one part of the story. I've not followed Javascript-the-platform that closely (i.e. anything much beyond jQuery) - what's your experience been like, working with Node and other libraries? It's "ok". The standard library shipping with node is lacking in areas (there's no flock(), there's no getopts parser, and a bunch of other things), and right now it feels like it is stagnating while they get in true Windows support, but I've been surprised by the breadth of things available on npm (the equivalent of cpan). Perl->Javascript is a really interesting migration path I'd not considered, and I'm not sure "it's faster!" would convince me on its own -- we all know there are faster languages than Perl. But... JS does have a significant advantages over, say, Perl->Haskell, as Javascript is so widespread and therefore has many(devs, projects, jobs). OK let me put it another way than just "faster" - it's the fastest option for dynamic languages (with the possible exception of Lua-JIT) that has a sane (ALGOL-style) syntax, while still having a large user base. My thinking behind Haraka is that a lot of web sites need a mail server with custom functionality, and their web site coders know Javascript, so why not provide them with an option to do stuff in JS for email. Also the other huge thing for me is I've been writing async code in Perl now for years, and you always come across fighting with some library because it's got a blocking API so either you can't use it, or you take a risk and block the event loop while it runs (the same is true for Twisted or the Ruby one). That just doesn't happen in Node - everything is async. Matt. __ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email __
Re: Cool/useful short examples of Perl?
On 08/06/11 13:41, Paul Makepeace wrote:
On Wed, Jun 8, 2011 at 13:17, Tom Hukins wrote:
On Wed, Jun 08, 2011 at 02:00:41PM +0200, Abigail wrote:
I'd rather go for sacking people that don't know the difference
between
if (something) { ... }
and
unless (!something) { ... }
It's sunny outside and pubs are open: I can think of worse times to
lose my job.
Or does everyone think they are always equivalent?
I'm not everyone, and with a language as flexible as Perl I hesitate
to make strong statements involving words like "always", but I don't
recall encountering a situation where they differ.
$ perl -le 'print "$_ == !!$_ ? ", $_ == !!$_ ? "yes" : "no" for (-1,
0, 1, 2, undef)'
-1 == !!-1 ? no
0 == !!0 ? yes
1 == !!1 ? yes
2 == !!2 ? no
== !! ? yes
But:
$ perl -le 'print 0 eq !!0 ? "yes" : "no"'
no
This still wouldn't affect the behaviour of the original example. In the
context of an if or unless statement, the only thing that matters is the
boolean value of the expression, not exactly which true or false value
it is. Perl's canonical true and false are 1 and '' respectively, but
everything has a boolean value.
Matt
Re: Cool/useful short examples of Perl?
On Wed, Jun 8, 2011 at 14:15, Kaoru wrote:
> On Wed, Jun 8, 2011 at 1:41 PM, Paul Makepeace wrote:
>> $ perl -le 'print "$_ == !!$_ ? ", $_ == !!$_ ? "yes" : "no" for (-1,
>> 0, 1, 2, undef)'
>> -1 == !!-1 ? no
>> 0 == !!0 ? yes
>> 1 == !!1 ? yes
>> 2 == !!2 ? no
>> == !! ? yes
>
> Whether they are equal according to "==" shouldn't matter here, should
> it? What matters between if(something) and unless (!something) is
> whether something and !!something are the same boolean-wise.
>
> I think this code shows they are all the same?
Yes, you're right - perl doesn't use == semantics for that.
$ perl -e 'for ("a", "", -1, 0, 1, 2, undef) {
print "$_: ";
if ($_) {
unless (!$_) { print "ok" } else { print "not ok" }
} else {
unless (!$_) { print "not ok" } else { print "ok" }
}
print "\n" }'
a: ok
: ok
-1: ok
0: ok
1: ok
2: ok
: ok
A legitimate use of unless + else! :-)
P
Re: Cool/useful short examples of Perl?
On 8 Jun 2011, at 13:41, Paul Makepeace wrote:
> On Wed, Jun 8, 2011 at 13:17, Tom Hukins wrote:
>> On Wed, Jun 08, 2011 at 02:00:41PM +0200, Abigail wrote:
>>> I'd rather go for sacking people that don't know the difference
>>> between
>>>
>>> if (something) { ... }
>>>
>>> and
>>>
>>> unless (!something) { ... }
>>
>> It's sunny outside and pubs are open: I can think of worse times to
>> lose my job.
>>
>>> Or does everyone think they are always equivalent?
>>
>> I'm not everyone, and with a language as flexible as Perl I hesitate
>> to make strong statements involving words like "always", but I don't
>> recall encountering a situation where they differ.
>
> $ perl -le 'print "$_ == !!$_ ? ", $_ == !!$_ ? "yes" : "no" for (-1,
> 0, 1, 2, undef)'
> -1 == !!-1 ? no
> 0 == !!0 ? yes
> 1 == !!1 ? yes
> 2 == !!2 ? no
> == !! ? yes
Well, -1 may not equal !!-1, but truthwise it's the same, so it's the same to
an if or unless statement.
I realise this is getting a bit silly, but:
foreach my $test_item (-1, 0, 1, 2, undef, '') {
print "$test_item:\t"
. return_truth_by_if_not($test_item) . ', '
. return_truth_by_unless($test_item) . ', '
. return_truth_by_if_not(!$test_item) . ', '
. return_truth_by_unless(!$test_item) . ', '
. return_truth_by_if_not(!!$test_item) . ', '
. return_truth_by_unless(!!$test_item) . "\n";
}
sub return_truth_by_if_not {
my $value = shift;
if (!$value) {
return 'non';
}
else {
return 'oui';
}
}
sub return_truth_by_unless {
my $value = shift;
unless ($value) {
return 'non';
}
else {
return 'oui';
}
}
--
David Matthewman
Re: Cool/useful short examples of Perl?
> From: london.pm-requ...@london.pm.org > Subject: london.pm Digest, Vol 68, Issue 13 > To: london.pm@london.pm.org > Date: Wed, 8 Jun 2011 14:00:37 +0100 > > Send london.pm mailing list submissions to > london.pm@london.pm.org > > To subscribe or unsubscribe via the World Wide Web, visit > http://london.pm.org/mailman/listinfo/london.pm > or, via email, send a message with subject or body 'help' to > london.pm-requ...@london.pm.org > > You can reach the person managing the list at > london.pm-ow...@london.pm.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of london.pm digest..." > > > Today's Topics: > > 1. Re: Someone needs to take jwz aside... (Paul Makepeace) > 2. Re: Someone needs to take jwz aside... (Denny) > 3. Re: Someone needs to take jwz aside... (Peter Edwards) > 4. Re: Cool/useful short examples of Perl? (Abigail) > 5. Re: Cool/useful short examples of Perl? (Bill Crawford) > 6. Re: Cool/useful short examples of Perl? (Tom Hukins) > 7. Re: Cool/useful short examples of Perl? (Paul Makepeace) > 8. Re: Cool/useful short examples of Perl? (Peter Corlett) > 9. Re: Cool/useful short examples of Perl? (Roger Burton West) > 10. Re: Cool/useful short examples of Perl? (David Matthewman) > > > -- > > Message: 1 > Date: Wed, 8 Jun 2011 12:07:01 +0100 > From: Paul Makepeace > Subject: Re: Someone needs to take jwz aside... > To: "London.pm Perl M[ou]ngers" > Message-ID: > Content-Type: text/plain; charset=ISO-8859-1 > > On Wed, Jun 8, 2011 at 11:21, David Cantrell wrote: > > Of course, it's possible that the Comprehensive Python Archive Network > > or similar for ruby/javascript/java/C/whatever does exist but I just > > can't find it. ?But then, if I can't find it, it's not much use. > > (If you were a python programmer and yet had still somehow managed to > assiduously avoid all mentions of it, you could search for 'python > packages' (because that's what they're called in python) and would > find the top result is http://pypi.python.org/pypi) > > > Paul > > > > -- > > Message: 2 > Date: Wed, 08 Jun 2011 12:15:51 +0100 > From: Denny <2...@denny.me> > Subject: Re: Someone needs to take jwz aside... > To: "London.pm Perl M[ou]ngers" > Message-ID: <1307531751.13033.12.ca...@serenity.denny.me> > Content-Type: text/plain; charset="utf-8" > > On Wed, 2011-06-08 at 12:07 +0100, Paul Makepeace wrote: > > On Wed, Jun 8, 2011 at 11:21, David Cantrell wrote: > > > Of course, it's possible that the Comprehensive Python Archive Network > > > or similar for ruby/javascript/java/C/whatever does exist but I just > > > can't find it. But then, if I can't find it, it's not much use. > > > > (If you were a python programmer and yet had still somehow managed to > > assiduously avoid all mentions of it, you could search for 'python > > packages' (because that's what they're called in python) and would > > find the top result is http://pypi.python.org/pypi) > > As helpfully documented here: > http://wiki.python.org/moin/MovingToPythonFromOtherLanguages > > -- next part -- > A non-text attachment was scrubbed... > Name: not available > Type: application/pgp-signature > Size: 490 bytes > Desc: This is a digitally signed message part > Url : > http://london.pm.org/pipermail/london.pm/attachments/20110608/5c15a72b/attachment-0001.pgp > > -- > > Message: 3 > Date: Wed, 8 Jun 2011 12:19:15 +0100 > From: Peter Edwards > Subject: Re: Someone needs to take jwz aside... > To: "London.pm Perl M[ou]ngers" > Message-ID: > Content-Type: text/plain; charset=ISO-8859-1 > > > > > On Wed, 8 Jun 2011, David Cantrell wrote: > > > > It's the lack of a CPAN-a-like for any other language that keeps me > >> coming back to perl. > >> > >> Of course, it's possible that the Comprehensive Python Archive Network > >> or similar for ruby/javascript/java/C/whatever does exist but I just > >> can't find it. But then, if I can't find it, it's not much use. > >> > >> > >> Python repo > http://pypi.python.org/pypi > > It was fairly chastening a couple of years back looking for a library > implementing Role Based Access Control and finding that there was a Python > one but no Perl one >
Re: Cool/useful short examples of Perl?
On Wed, Jun 8, 2011 at 1:41 PM, Paul Makepeace wrote: > $ perl -le 'print "$_ == !!$_ ? ", $_ == !!$_ ? "yes" : "no" for (-1, > 0, 1, 2, undef)' > -1 == !!-1 ? no > 0 == !!0 ? yes > 1 == !!1 ? yes > 2 == !!2 ? no > == !! ? yes Whether they are equal according to "==" shouldn't matter here, should it? What matters between if(something) and unless (!something) is whether something and !!something are the same boolean-wise. I think this code shows they are all the same? $ perl -le 'print "$_\tis the same booleanwise as\t!!$_\t", !($_ xor !!$_) ? "yes" : "no" for (-1, 0, 1, 2, undef)' -1 is the same booleanwise as !!-1yes 0 is the same booleanwise as !!0 yes 1 is the same booleanwise as !!1 yes 2 is the same booleanwise as !!2 yes is the same booleanwise as !! yes - As has been pointed out "!" can be overridden etc, but I think the use of unless is safer than your example suggested. - Alex
Re: Cool/useful short examples of Perl?
On 8 Jun 2011, at 13:17, Tom Hukins wrote:
> On Wed, Jun 08, 2011 at 02:00:41PM +0200, Abigail wrote:
>> I'd rather go for sacking people that don't know the difference
>> between
>>
>>if (something) { ... }
>>
>> and
>>
>>unless (!something) { ... }
>
> It's sunny outside and pubs are open: I can think of worse times to
> lose my job.
>
>> Or does everyone think they are always equivalent?
>
> I'm not everyone, and with a language as flexible as Perl I hesitate
> to make strong statements involving words like "always", but I don't
> recall encountering a situation where they differ.
Their side effects are different. There may be a simpler way to demonstrate
this, but for instance:
#! /usr/bin/env perl
print "unless: ";
print use_unless() . "\n";
print "if: ";
print use_if() . "\n";
sub use_unless {
my $value = 1;
unless ($value) {
# nop
}
}
sub use_if {
my $value = 1;
if (!$value) {
# nop
}
}
--
David Matthewman
Re: Cool/useful short examples of Perl?
On Wed, Jun 08, 2011 at 01:41:29PM +0100, Paul Makepeace wrote: >$ perl -le 'print "$_ == !!$_ ? ", $_ == !!$_ ? "yes" : "no" for (-1, >0, 1, 2, undef)' >-1 == !!-1 ? no >0 == !!0 ? yes >1 == !!1 ? yes >2 == !!2 ? no > == !! ? yes Might as well add lua, since I'm trying to learn it at the moment (and therefore this is unlikely to be idiomatic). Having explicit boolean types makes it all a bit more predictable, I feel. $ lua -e 'function process(x) y=not not x;print(x,"==",y,"?",(y==x)) end for x=-1,2 do process(x) end process(nil) process(true) process(false)' -1 == true? false 0 == true? false 1 == true? false 2 == true? false nil == false ? false true== true? true false == false ? true Roger
Re: Cool/useful short examples of Perl?
On 8 Jun 2011, at 13:00, Abigail wrote:
[...]
> I'd rather go for sacking people that don't know the difference
> between
>if (something) { ... }
> and
>unless (!something) { ... }
> Or does everyone think they are always equivalent?
Is this a trick question?
I would expect it to be equivalent if "something" is an expression with higher
precedence than "!". If not, I'd be fascinated to know what the
counterintuitive behaviour is and why somebody thought it was a good idea. (And
also how I've managed to treat them as equivalent for years and not get burned.)
For "something" being arbitrary text, no. if($foo && $bar) and unless(!$foo &&
$bar) are of course not equivalent.
I do like "unless". It's more visible than "!". I like it enough that I'll
invert the sense of an expression using De Morgan's law and use unless to
eliminate those oft-missed plings. Avoiding misreading trumps avoiding ugliness.
Re: Cool/useful short examples of Perl?
On Wed, Jun 8, 2011 at 13:17, Tom Hukins wrote:
> On Wed, Jun 08, 2011 at 02:00:41PM +0200, Abigail wrote:
>> I'd rather go for sacking people that don't know the difference
>> between
>>
>> if (something) { ... }
>>
>> and
>>
>> unless (!something) { ... }
>
> It's sunny outside and pubs are open: I can think of worse times to
> lose my job.
>
>> Or does everyone think they are always equivalent?
>
> I'm not everyone, and with a language as flexible as Perl I hesitate
> to make strong statements involving words like "always", but I don't
> recall encountering a situation where they differ.
$ perl -le 'print "$_ == !!$_ ? ", $_ == !!$_ ? "yes" : "no" for (-1,
0, 1, 2, undef)'
-1 == !!-1 ? no
0 == !!0 ? yes
1 == !!1 ? yes
2 == !!2 ? no
== !! ? yes
FWIW,
$ python -c 'for x in -1, 0, 1, 2, None: nnx = not not x; print x,
"==", nnx, "?", "yes" if x == nnx else "no"'
-1 == True ? no
0 == False ? yes
1 == True ? yes
2 == True ? no
None == False ? no
(Wait, what? Command line python? Semicolons? Ternary ops?)
Paul
Re: Cool/useful short examples of Perl?
On Wed, Jun 08, 2011 at 02:00:41PM +0200, Abigail wrote:
> I'd rather go for sacking people that don't know the difference
> between
>
> if (something) { ... }
>
> and
>
> unless (!something) { ... }
It's sunny outside and pubs are open: I can think of worse times to
lose my job.
> Or does everyone think they are always equivalent?
I'm not everyone, and with a language as flexible as Perl I hesitate
to make strong statements involving words like "always", but I don't
recall encountering a situation where they differ.
In response to your question, I started out thinking about "zero but
true" values, but this doesn't matter because double negation of
truthfulness won't care about the value. So I got stuck.
The only special situation I can think of would be when someone
overloads the "!" operator. I would console anyone doing this on code
I maintain by mentioning that it's sunny outside and pubs are open.
I suspect I've missed lots of other interesting syntactical
peculiarities, though. Would you mind sharing them?
Tom
Re: Cool/useful short examples of Perl?
On 8 June 2011 13:00, Abigail wrote:
> I'd rather go for sacking people that don't know the difference
> between
>
> if (something) { ... }
>
> and
>
> unless (!something) { ... }
>
>
>
> Or does everyone think they are always equivalent?
There are those (though I wouldn't be so stern) who would advocate
sacking people who wrote overloaded operators that made them not do
the same thing :)
> Abigail
Will.
Re: Cool/useful short examples of Perl?
On Wed, Jun 08, 2011 at 09:24:50AM +0100, Dirk Koopman wrote:
> On 08/06/11 08:31, Abigail wrote:
>>
>>
>> unless (!something) {
>> ...
>> }
>> else {
>> ... # Unless not something isn't true.
>> }
>>
>
> An earnest question in the interview test along the lines of "what does
> this mean and when would you use it" should weed several people out.
>
> Instant sacking (or promotion if in Britain) on sight would seem to be
> an answer.
>
I'd rather go for sacking people that don't know the difference
between
if (something) { ... }
and
unless (!something) { ... }
Or does everyone think they are always equivalent?
Abigail
Re: Someone needs to take jwz aside...
> > On Wed, 8 Jun 2011, David Cantrell wrote: > > It's the lack of a CPAN-a-like for any other language that keeps me >> coming back to perl. >> >> Of course, it's possible that the Comprehensive Python Archive Network >> or similar for ruby/javascript/java/C/whatever does exist but I just >> can't find it. But then, if I can't find it, it's not much use. >> >> >> Python repo http://pypi.python.org/pypi It was fairly chastening a couple of years back looking for a library implementing Role Based Access Control and finding that there was a Python one but no Perl one http://pypi.python.org/pypi?%3Aaction=search&term=role+based+access+control&submit=search http://search.cpan.org/search?query=role+based+access+control&mode=all Then when I was doing WxWidgets programming from ActivePerl having to use the wxPython library docs http://www.wxpython.org/ because they were more up to date and complete than the Perl ones http://wxperl.sourceforge.net/documentation.html in terms of calling from a wrapper (more useful than the C++ docs). Node.js repo http://npm.mape.me/ V8 seems to work well on Unix and takes little code to implement an event-driven networking app using server-side JS. If you can get over the 'Nam-style flashbacks to old skool javascript hacks for IE5.0 Regards, Peter http://perl.dragonstaff.co.uk
Re: Someone needs to take jwz aside...
On Wed, 2011-06-08 at 12:07 +0100, Paul Makepeace wrote: > On Wed, Jun 8, 2011 at 11:21, David Cantrell wrote: > > Of course, it's possible that the Comprehensive Python Archive Network > > or similar for ruby/javascript/java/C/whatever does exist but I just > > can't find it. But then, if I can't find it, it's not much use. > > (If you were a python programmer and yet had still somehow managed to > assiduously avoid all mentions of it, you could search for 'python > packages' (because that's what they're called in python) and would > find the top result is http://pypi.python.org/pypi) As helpfully documented here: http://wiki.python.org/moin/MovingToPythonFromOtherLanguages signature.asc Description: This is a digitally signed message part
Re: Someone needs to take jwz aside...
On Wed, Jun 8, 2011 at 11:21, David Cantrell wrote: > Of course, it's possible that the Comprehensive Python Archive Network > or similar for ruby/javascript/java/C/whatever does exist but I just > can't find it. But then, if I can't find it, it's not much use. (If you were a python programmer and yet had still somehow managed to assiduously avoid all mentions of it, you could search for 'python packages' (because that's what they're called in python) and would find the top result is http://pypi.python.org/pypi) Paul
Re: Someone needs to take jwz aside...
On Wed, 8 Jun 2011, David Cantrell wrote: It's the lack of a CPAN-a-like for any other language that keeps me coming back to perl. Of course, it's possible that the Comprehensive Python Archive Network or similar for ruby/javascript/java/C/whatever does exist but I just can't find it. But then, if I can't find it, it's not much use. ruby does have rubygems.org now and they have almost decided that it is the canonical archive. (rubyforge and github being previous choices). All though there has beeen a schism over what tool to use to install gems. http://slimgems.github.com/ of course it may fail on your definition of comprehensive :) Lets put it this way. Im happy to be back sysadmining a perl stack instead of a ruby stack :) -- bob walker everything should be purple and bendy http://randomness.org.uk
Re: Someone needs to take jwz aside...
On Wed, Jun 08, 2011 at 09:06:48AM +0100, Hakim Cassimally wrote: > While Javascript-the-language is lovely (as you say, better in some > respects, worse in others, than Perl), that's only one part of the > story. I've not followed Javascript-the-platform that closely (i.e. > anything much beyond jQuery) - what's your experience been like, > working with Node and other libraries? > > Perl->Javascript is a really interesting migration path I'd not > considered, and I'm not sure "it's faster!" would convince me on its > own -- we all know there are faster languages than Perl. But... JS > does have a significant advantages over, say, Perl->Haskell, as > Javascript is so widespread and therefore has many(devs, projects, > jobs). The huge problem I have with programming in Javascript is that, apart from a few competing libraries for doing browsery stuff, which I'm not really interested in, there's not much else. Perl's strength isn't its speed (there are faster languages for just about every task apart from munging text, and little that I do these days has speed of text munging as a priority) or the language itself (which is a bit of a dog's breakfast) but is the CPAN. It's the lack of a CPAN-a-like for any other language that keeps me coming back to perl. Of course, it's possible that the Comprehensive Python Archive Network or similar for ruby/javascript/java/C/whatever does exist but I just can't find it. But then, if I can't find it, it's not much use. -- David Cantrell | Hero of the Information Age The test of the goodness of a thing is its fitness for use. If it fails on this first test, no amount of ornamentation or finish will make it any better, it will only make it more expensive and foolish. -- Frank Pick, lecture to the Design and Industries Assoc, 1916
Re: Someone needs to take jwz aside...
On 06/08/2011 11:21 AM, David Cantrell wrote: Of course, it's possible that the Comprehensive Python Archive Network or similar for ruby/javascript/java/C/whatever does exist but I just can't find it. But then, if I can't find it, it's not much use. Perly people were working on a "JSAN" several years ago. I have no idea what the status is (which rather proves your point, I suspect). http://openjsan.org/ Dave...
Re: 4th edition
On 06/08/2011 09:41 AM, Steve Mynott wrote: Apparently out in October! It's on the O'Reilly site, so it must be true :) http://oreilly.com/catalog/9780596004927/ Dave...
4th edition
Apparently out in October! I assume "Programming Perl6" will be out in 2021 by which time Centos 7 will have 5.14. -- Steve Mynott
Re: Cool/useful short examples of Perl?
On Wed, Jun 8, 2011 at 08:31, Abigail wrote:
> On Wed, Jun 08, 2011 at 07:46:52AM +0200, Richard Foley wrote:
>> I've found a lot of German programmers very uncomfortable with the "unless"
>> keyword, (or maybe it's just c programmers). They appear to very often
>> prefer
>> to use a construct of the form:
>>
>> if ( !something ) { ...
>>
>> Even worse is:
>>
>> unless ( !something ) { ...
>>
>> The brain just into tailspin goes.
>
>
> unless (!something) {
> ...
> }
> else {
> ... # Unless not something isn't true.
dont(...);
> }
Joking aside, I wonder if part of the confusion with unless is that
it's usually associated with some kind of negative when it's in the
prefix form "Unless (you'll be in trouble | don't ... | ruh-roh)"
Paul
Re: Cool/useful short examples of Perl?
On 08/06/11 08:31, Abigail wrote:
unless (!something) {
...
}
else {
... # Unless not something isn't true.
}
An earnest question in the interview test along the lines of "what does
this mean and when would you use it" should weed several people out.
Instant sacking (or promotion if in Britain) on sight would seem to be
an answer.
Dirk
Re: Someone needs to take jwz aside...
On 7 June 2011 16:22, Matt Sergeant wrote: > As someone else who has written a bunch of popular perl stuff over the > years, I'll chime in here too - I write a lot less open source stuff these > days, but when I do I'm looking much more to JavaScript. The language is > actually about as good as Perl (some areas better, some worse), but the > implementation, the interpreters, are just WAY faster. > > https://github.com/baudehlo/Haraka Javascript proponents always used to say that the language would scrub up quite nicely if browser vendors actually bothered to work on it! And of course, being a much *simpler* language than Perl, it's not surprising that it's been possible to apply some great optimisations on it. Some more details and write-up on your actual benchmarks would be really interesting. While Javascript-the-language is lovely (as you say, better in some respects, worse in others, than Perl), that's only one part of the story. I've not followed Javascript-the-platform that closely (i.e. anything much beyond jQuery) - what's your experience been like, working with Node and other libraries? Perl->Javascript is a really interesting migration path I'd not considered, and I'm not sure "it's faster!" would convince me on its own -- we all know there are faster languages than Perl. But... JS does have a significant advantages over, say, Perl->Haskell, as Javascript is so widespread and therefore has many(devs, projects, jobs). osf'
Re: Cool/useful short examples of Perl?
On Wed, Jun 08, 2011 at 07:46:52AM +0200, Richard Foley wrote:
> I've found a lot of German programmers very uncomfortable with the "unless"
> keyword, (or maybe it's just c programmers). They appear to very often
> prefer
> to use a construct of the form:
>
> if ( !something ) { ...
>
> Even worse is:
>
> unless ( !something ) { ...
>
> The brain just into tailspin goes.
unless (!something) {
...
}
else {
... # Unless not something isn't true.
}
Abigail
