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Why I’m Learning Perl 6

evanmiller.org

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Re: Why I’m Learning Perl 6

#351

Post by cutler »

16bytes wrote: post #347
cutler wrote: post #331

Earlier quoted context omitted.

Better math is one good reason. Grammars are also a great feature of Perl 6.

I've never faced a problem in another modern language where math became a big problem. Even using something like numpy made never made me frustrated with, say, python's numerical types. From what I've seen perl6 makes some operations more convenient. Cool, I guess, but not a great reason to reach for perl6. Grammars are really cool, and one reason I might reach for perl6, but you also have really great special-purpos…

I should have been more specific. Try this in Ruby, Python, PHP or Javascript: 0.1 + 0.2 - 0.3 . You'll get an approximation in most languages but only Perl 6 returns 0.

Re: Why I’m Learning Perl 6

#352

Post by zimpenfish »

cutler wrote: post #351
16bytes wrote: post #347

Earlier quoted context omitted.

I've never faced a problem in another modern language where math became a big problem. Even using something like numpy made never made me frustrated with, say, python's numerical types. From what I've seen perl6 makes some operations more convenient. Cool, I guess, but not a great reason to reach for perl6. Grammars are really cool, and one reason I might reach for perl6, but you also have really great special-purpos…

I should have been more specific. Try this in Ruby, Python, PHP or Javascript: 0.1 + 0.2 - 0.3 . You'll get an approximation in most languages but only Perl 6 returns 0.

Go also returns 0.

https://play.golang.org/p/M_AJXIBAeX

Re: Why I’m Learning Perl 6

#353

Post by chromatic »

cygx wrote: post #272
kbenson wrote: post #258

Earlier quoted context omitted.

Ah, I figured that part was slightly off (since I knew PBC was bytecode and thus my waffling with "bytecode syntaxes"), but really didn't want to research the history I had already forgotten. Thanks for the correction. > Besides PIR, other languages still close to the metal were NQP versions (though I don't remember the exact relationship between NQP/NQP-rx/parrot-nqp) and eventually Winxed. I vaguely remember NQP/NQ…

Winxed was NotFound's brainchild, though I believe Whiteknight did push its usage. The way I remember it, the issue was that later versions of NQP moved towards greater backend independence and no longer mapped directly to Parrot VM semantics (eg 6model), so Parrot had to rely on older NQP version, making Winxed an attractive alternative.

That's close to what happened.

The first relevant version of compiler tools were called PGE/TGE, written in PIR and based on the notion of attribute grammars and grammar engines. The first versions of NQP grew out of those.

I believe early versions of NQP were hosted in the Parrot repo, but they started to be developed out of tree and eventually were completely hosted out of the tree.

NQP was an improvement over PGE/TGE in many ways, so some of Parrot's internal tools were created in or ported to NQP.

Eventually (I believe with NQP-rx), NQP forked into an incompatible version out of tree. As you mention, when the next incompatible revision of NQP was being planned, it was no longer an attractive target for Parrot, because it was:

  * developed out of tree
  * developed out of Parrot's release cycle
  * backwards incompatible
  * "backend independent"
In particular, migrating existing, working Parrot tools to a new language which offered little beyond busywork to gain "backend independence" wasn't worth the effort. (Having NQP go unsupported for existing tools wasn't great either, especially given that one explanation for "backend independence" was that Parrot tools weren't evolving fast enough to support Rakudo features -- still feels like a circular argument.)

I still maintain that it made little sense for Parrot to depend on an external project, evolving rapidly, offering little stability, with the express intent to obviate Parrot.

Re: Why I’m Learning Perl 6

#354

Post by 16bytes »

cutler wrote: post #351
16bytes wrote: post #347

Earlier quoted context omitted.

I've never faced a problem in another modern language where math became a big problem. Even using something like numpy made never made me frustrated with, say, python's numerical types. From what I've seen perl6 makes some operations more convenient. Cool, I guess, but not a great reason to reach for perl6. Grammars are really cool, and one reason I might reach for perl6, but you also have really great special-purpos…

I should have been more specific. Try this in Ruby, Python, PHP or Javascript: 0.1 + 0.2 - 0.3 . You'll get an approximation in most languages but only Perl 6 returns 0.

Yes, I understand the example. It's a classic floating point numbers demonstration.

What I am saying is that I have not encountered a real-life case where this would have made my life easier.

Again, it's neat, but not a real reason to move to a new language.

Re: Why I’m Learning Perl 6

#355

Post by petre »

aduitsis wrote: post #2

Read the article, very informative. Pleasantly surprised to find out that it doesn't mention at all language traits like syntax, but focuses on the features of Perl6's underlying VM, specifically MoarVM.

Well, it should have mentioned Perl6 uses rational number math instead of floating point. I think this is a big advantage, since you can do more precise calculations using just the core language.

Re: Why I’m Learning Perl 6

#356

Post by petre »

16bytes wrote: post #354
cutler wrote: post #351

Earlier quoted context omitted.

I should have been more specific. Try this in Ruby, Python, PHP or Javascript: 0.1 + 0.2 - 0.3 . You'll get an approximation in most languages but only Perl 6 returns 0.

Yes, I understand the example. It's a classic floating point numbers demonstration. What I am saying is that I have not encountered a real-life case where this would have made my life easier. Again, it's neat, but not a real reason to move to a new language.

Banking/accounting software? Generating reports that are expected to return correct data w/o cumulative errors from flating point arithmetic? After all, Perl is the Practical Extraction and Report Language.

Re: Why I’m Learning Perl 6

#357

Post by petre »

dmytrish wrote: post #152
bloobloobloo wrote: post #133

Earlier quoted context omitted.

> 10 different ways of doing the same thing Mostly an urban myth. Where it isn't, at least 8 of those ways are actually important. Exercise: write a python program that prints Python's quoting documentation, without external files, without editing the documentation. Spoiler alert: it's impossible.

So, how exactly these different ways of getting sub arguments are useful? sub add1 { my ($arg1, $arg2) = @_; $arg1 + $arg2; } sub add2 { my $arg1 = shift; # possibly two screens of dense code here, then my $arg2 = shift; $arg1 + $arg2; } sub add3 { $_[0] + $_[1] } # There may be some other ways to extract arguments # that I am not aware of. # It's possible to combine any of the methods! And this is just argument acce…

The second example is just bad code. The third example one would rarely use in oneliners or very shorts subs, maybe in a dispatch table. You can write atrocious code in just about any language. Perl 5.20 finally has function signatures anyway.

Re: Why I’m Learning Perl 6

#358

Post by petre »

cutler wrote: post #333

Perl 6 carries 2 pieces of baggage from its predecessor - prefixing variables with "my" to create lexical scope and the obligatory "use v6;" at the top of every script. Why can't an advanced language like Perl 6 scope variables without littering "my" everywhere? You don't see it in any other mainstream language I can think of.

How is this different than prefixing variables with var in JavaScript?

Re: Why I’m Learning Perl 6

#359

Post by bloobloobloo »

gjm11 wrote: post #143
bloobloobloo wrote: post #133

Earlier quoted context omitted.

> 10 different ways of doing the same thing Mostly an urban myth. Where it isn't, at least 8 of those ways are actually important. Exercise: write a python program that prints Python's quoting documentation, without external files, without editing the documentation. Spoiler alert: it's impossible.

I'm not sure I understand your exercise. What do you mean by "Python's quoting documentation", and what do you mean by "editing" it?

> What do you mean by "Python's quoting documentation"

String literals are described by the following lexical definitions:

   stringliteral:   shortstring | longstring
   shortstring:     "'" shortstringitem* "'" | '"' shortstringitem* '"'
   longstring:      "'''" longstringitem* "'''" | '"""' longstringitem* '"""'
   shortstringitem: shortstringchar | escapeseq
   longstringitem:  longstringchar | escapeseq
   shortstringchar: 
   longstringchar:  
   escapeseq:       "\"
You can't paste that text into a file and write a Python program around it that outputs the same text. You need to encode the quote characters.

More generally, there is no way in (many languages including) Python to treat an arbitrary (yet known) block of data as data.

Re: Why I’m Learning Perl 6

#360

Post by bloobloobloo »

yorwba wrote: post #187
gjm11 wrote: post #143

Earlier quoted context omitted.

I'm not sure I understand your exercise. What do you mean by "Python's quoting documentation", and what do you mean by "editing" it?

I was wondering about that, too. Unless `"Python's quoting documentation"` is an easter-egg in "help()" that recursively contains a quoted version of itself, it should be possible to just escape all problematic characters. But maybe that counts as `"editing"`? Not sure.

> maybe that counts as `"editing"`

how would it not

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