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Differences Between Perl 5 and Perl 6

design.perl6.org

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Re: Differences Between Perl 5 and Perl 6

#91

Post by kbenson »

cwyers wrote: post #90
kbenson wrote: post #86

Earlier quoted context omitted.

1. Can't argue with this. 2. With Inline::Perl5[1] this should be a non-issue. The short code snippet in the README at the github repo referenced should give you the idea. 3. Having not been released yet, Perl 6 has zero history on backwards compatibility, so there's no way to assess whether it's relatively better or worse than Perl 5. That said, I don't necessarily support the original statement that Perl 6 is a sup…

> Having not been released yet, Perl 6 has zero history on backwards compatibility, so there's no way to assess whether it's relatively better or worse than Perl 5. Well, uh, it's not backwards-compatible with Perl 5. Yes, yes, I know, "It's a different language." So why is it called "Perl 6?" The name is very much designed to tell us "this is the one after Perl 5." Insisting that everyone evaluate it as a greenfield…

But with Inline::Perl5, it is, which I keep trying to point out. I think Inline::Perl5 may be a bad name for what is essentially "Interop with all your Perl 5 code and modules seamlessly in Perl 6, including XS".

Re: Differences Between Perl 5 and Perl 6

#92

Post by acqq »

cwyers wrote: post #90
kbenson wrote: post #86

Earlier quoted context omitted.

1. Can't argue with this. 2. With Inline::Perl5[1] this should be a non-issue. The short code snippet in the README at the github repo referenced should give you the idea. 3. Having not been released yet, Perl 6 has zero history on backwards compatibility, so there's no way to assess whether it's relatively better or worse than Perl 5. That said, I don't necessarily support the original statement that Perl 6 is a sup…

> Having not been released yet, Perl 6 has zero history on backwards compatibility, so there's no way to assess whether it's relatively better or worse than Perl 5. Well, uh, it's not backwards-compatible with Perl 5. Yes, yes, I know, "It's a different language." So why is it called "Perl 6?" The name is very much designed to tell us "this is the one after Perl 5." Insisting that everyone evaluate it as a greenfield…

> is an incredible insistence upon cognitive dissonance.

It seems like one more (maybe even initially unintentional, I don't know) gag of many of them. Python was named after Monty Python, but Perl 6 lives a Monty Python life. Remember the "Parrot"? The support for it in Rakudo was suspended only some months ago:

http://pmthium.com/2015/02/suspending-rakudo-parrot/

The Parrot was of course named after the most famous "Dead Parrot Sketch."

Reading about the "announcement" on the Pigdog site was of course completely fitting. An another site covered the beginning of the presentation:

http://www.10zenmonkeys.com/2015/10/06/the-night-larry-wall-...

"At 7:30 the room grew quiet, and the small throng of geeks migrated into the "Kanbar Forum" room." "There was already a browser on the screen that was displaying the Perl6 home page at Perl6.org, and two more tabs appeared to be IRC logs "for #p..." The quiet chatter turned to applause when Larry Wall finally walked out onto the stage. Then he made shadow puppets on the screen with his fingers — and left."

Once you accept the spirit, it's clear that nothing should remain "sacred." Not even the consistent naming of the language.

Re: Differences Between Perl 5 and Perl 6

#93

Post by singingfish »

acqq wrote: post #72
nandhp wrote: post #43

Do the changes to the regular expression syntax seem woefully under-publicized here? Was: $str =~ m/^\d{2,5}\s/i Now: $str ~~ m:P5:i/^\d{2,5}\s/ # :P5 indicates Perl5-compatibile regex syntax Was: $str =~ s/(a)/$1/e; Now: $str ~~ s:P5/(a)/{$0}/; # $1 is now $0 I actually find the change from $1 to $0 particularly disturbing, since that is well standardized and group 0 normally refers to the whole matched pattern (tho…

It seems "disturbing" is the good word here, as the kind of changes in the semantics or notation between Perl 5 and Perl 6 almost guarantees that most potential users would have to decide if they are going to reject using one or another: The need to "read differently" on the distant look similar code demands too much from the people who'd just like to "get the job done." What's that $1? Well it's the first match if i…

don't use $1, use named captures or list assignment. qr/\$\d+/ is a oneliner thing or a code smell.

Re: Differences Between Perl 5 and Perl 6

#94

Post by [deleted] »

wvenable wrote: post #53
spathi_fwiffo wrote: post #45

Earlier quoted context omitted.

That does shed some insight into why a generic Length is missing, but I agree with the sentiment that it is counter intuitive. It does not read right on a quick scan, and I think this is especially important in softly typed languages. If I see string.chars I expect to see a bucket of char, and not the count of chars. That name needs to be more explicit.

It's terse which is another curse or benefit of Perl. The less terse method name would be string.numchars or string.charcount.

[deleted]

Re: Differences Between Perl 5 and Perl 6

#95

Post by sanderjd »

kamaal wrote: post #71
mirceal wrote: post #44

Earlier quoted context omitted.

IMHO Perl 6 will not catch on / be even mildly successful without a clear upgrade path from Perl 5. The ask for people to use Perl6 is a huge one given it's basically a completely different beast that just resembles Perl5. Without pointing out where Perl6 excels (in comparison to Python/Ruby not Perl5) this will probably be a non-starter for most people. (this is from somebody who did his fair share of Perl5 in the o…

Sorry I don't get it. Why would I rewrite an entire ecosystem in a new language, especially when Perl 5 is very well supported. Perl 5 code will remain as is. Perl 6 is for new projects. And if I'm familiar with Perl 5, it makes all the more sense to use it for my new projects. For non Perl programmers it makes a nice new language to learn.

I'm curious, because I haven't seen much discussion on this point: Ignoring that it is called Perl 6 and has it's lineage in a well-known language called Perl 5, what are some of its advantages over some of the other languages it will be considered alongside?

If I'm starting a new project, and I'm familiar with a bunch of other languages (including, but not limited to, Perl 5), what should draw me to Perl 6?

Re: Differences Between Perl 5 and Perl 6

#96

Post by ionforce »

Dylan16807 wrote: post #62
kstrauser wrote: post #50

Earlier quoted context omitted.

Ah, sorry. Despite having used Perl for years, I'd forgotten how much emphasis it puts on concepts that invoke a high cognitive load.

There is nothing "high cognitive load" about having different operators for addition and concatenation. I think it's simpler.

Who "adds two strings"? You're 1) converting the strings to ints 2) adding the ints.

The possibility of confusion is the part that is already complex.

Re: Differences Between Perl 5 and Perl 6

#97

Post by kbenson »

sanderjd wrote: post #95
kamaal wrote: post #71

Earlier quoted context omitted.

Sorry I don't get it. Why would I rewrite an entire ecosystem in a new language, especially when Perl 5 is very well supported. Perl 5 code will remain as is. Perl 6 is for new projects. And if I'm familiar with Perl 5, it makes all the more sense to use it for my new projects. For non Perl programmers it makes a nice new language to learn.

I'm curious, because I haven't seen much discussion on this point: Ignoring that it is called Perl 6 and has it's lineage in a well-known language called Perl 5, what are some of its advantages over some of the other languages it will be considered alongside? If I'm starting a new project, and I'm familiar with a bunch of other languages (including, but not limited to, Perl 5), what should draw me to Perl 6?

At this point Perl 6 is new enough that the use cases is excels at may not be well defined.

If you want to learn something new, and not be hampered by a feature in some other language not being supported (at this point the main feature is that it basically has all the features of all the languages), then trying out Perl 6 may be worth while. If nothing else, you've prototyped your project, found out what programming paradigms make sense and work well for your use case, and can switch to another language that offers that which achieves some other unmet goal of yours.

So, I guess that's a possible use case. Prototyping where you aren't sure what language features would be really useful and provide benefit later. Channels? Threads? Async? Promises? Lazy lists? Operator overloading? Roles? Grammars?

Re: Differences Between Perl 5 and Perl 6

#99

Post by btilly »

kbenson wrote: post #86
btilly wrote: post #84

Earlier quoted context omitted.

Perl6 is at least as good as Perl5 for everything Perl5 is good at. No. It is not. Don't believe me? Here is a short list of classic selling points for Perl 5 that Perl 6 clearly loses on. 1. Performance. Back in the 1990s, Perl hit a sweet spot of being quick for development while still being fast enough for a wide variety of tasks. It still performs reasonably well versus other scripting language. Every time I look…

1. Can't argue with this. 2. With Inline::Perl5[1] this should be a non-issue. The short code snippet in the README at the github repo referenced should give you the idea. 3. Having not been released yet, Perl 6 has zero history on backwards compatibility, so there's no way to assess whether it's relatively better or worse than Perl 5. That said, I don't necessarily support the original statement that Perl 6 is a sup…

On #1 we agree.

We don't agree on #2. Inline::Perl5 is better than I would expect, but there is still an issue. For example, Perl 6 uses garbage collection instead of reference counting so modules like http://search.cpan.org/dist/ReleaseAction/lib/ReleaseAction.... no longer work like they did in Perl 5. (Yes, that module is used in production code. And I happen to know of several independent re-creations of the same functionality that are used in the same ways in other production code.) I am sure there are other examples.

Granted, this a module that depends on a quirk of Perl 5 behavior. But even if only 5% of CPAN modules hit such a nasty quirk, dependency chains are long enough that most non-trivial applications will have some dependency that breaks somewhere. If I have a library that uses DBIx::Class, Moose, and Catalyst with some interesting plugins, would you care to bet money that it will work with no issues under Inline::Perl5?

On #3, what backwards compatibility means is "compatible with what you already have". Perl 6 immediately loses on that to Perl 5 because nobody has Perl 6 legacy code bases. Ideally this wouldn't be an important fact. But it is an important use case. Many organizations today are only staying on Perl because they do not want to rewrite their code. If they hit the point where they would be willing to do a Perl 5 to Perl 6 migration, there is no reason why they wouldn't consider a Perl 5 to Python 3 migration instead.

Re: Differences Between Perl 5 and Perl 6

#100

Post by systems »

mst wrote: post #87
a3n wrote: post #66

Earlier quoted context omitted.

Is there a Perl 5 EOL being discussed? Or, if Perl 5 and Perl 6 really are two completely separate languages separated by a similar syntax, then what comes after Perl 5 in the Perl 5 language? Will it forever be 5.N, 5.N+1, ...? (And, I guess, will there forever be 6.N, 6.N+1, ...?)

perl5 is a language name - its current release is version 22. I presume perl6 will be doing similarly.

mst as one of the biggest perl5 proponents are you planning to switch to perl6? 1. yes 2. no 3. maybe 4. will use both
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