Comparing PHP, Perl, Python and Ruby
hyperpolyglot.org
hyperpolyglot.org
That being said, it would also be useful to characterize features that are completely unique to a given language. For example, Python has 1) a unique and powerful version of super() for working with multiple inheritance; 2) it has generators (the yield statement) that allows state to be suspended and restarted (and allows data and/or exceptions to be passed back in to the generator); 3) the with-statement for managing contexts and for providing a new way to factor code; 4) easy-to-write class and function decorators; 5) metaclass support that provides full control over the creation of classes; 6) and descriptors for fine-control over attribute/method binding behavior.
Collectively, these capabilities make the language more than just another syntax for expressing the same ideas as other languages.
Perl has all these features.
1) a unique and powerful version of super() for working with multiple inheritance
Perl (with Moose) has before, after, around, override, and augment in addition to super. And, it has "Roles" so you don't have to resort to hacks like multiple inheritance to implement mixins or interfaces.
2) it has generators (the yield statement) that allows state to be suspended and restarted (and allows data and/or exceptions to be passed back in to the generator)
Perl has the library Coro, which allows multiple Perl and C stacks. With this coroutine and call-with-current-continuation are implemented.
3) the with-statement for managing contexts and for providing a new way to factor code
Perl has scope a few implementations of scope guards; Guard and Scope::Guard. It's not quite the same as with, because with's semantics around:
with open_file('foo') as f:
return f
sub x {
my $f = file('foo')->openr;
return $f; # $f is still open and ready for reading by the caller
}
sub x {
my $f = file('foo')->openr;
scope_guard { $f->close }
return $f; # caller gets a closed file object
}
This you don't really get, though you do get all of the things I've seen them used for in Python. You can even hack Perl syntax in a lexical scope, but that's evil so I will pretend it's impossible :)
5) metaclass support that provides full control over the creation of classes; 6) and descriptors for fine-control over attribute/method binding behavior
Moose. And unlike Python, there are libraries that take advantage of this to provide tiny bits of OO functionality that you can pick and choose from. Look on CPAN for a MooseX:: module, and chances are that the set of libraries you choose to use to augment a class will all work together.
The difference between Perl and Python is that Perl's features are implemented as modules, while Python's features are implemented in the core. That means that if you come up with a good idea, you can start using (and sharing) it immediately, while with Python, you have to wait until the next major release.
If you were to navigate a largish Perl codebase today, you'd encounter the old-school bless, Moose trickiness, and all kinds of variants on these themes. Extremely clever stuff that Damian Conway would give you a gold star for.
As usual Perl gives you everything you want, unless what you wanted was simplicity or standardization.
Sigh, please don't start language wars by stuff like assuming new programmers sits alone in an ivory tower and don't talk to people, read blogs or browse a new book. (Modern Perl discuss Moose before the old standard, for instance.)
Edit: I'm just not going to touch where you assume all Perl teams that write large code bases are too stupid to agree on best practices. (I'll ask this back instead: Why are there so many language wars-lovers in some open source communities...?)
Probably the same reason the French don't like the English or the Indians don't like the Pakistanis. The closer two things are to each other, the more passionate people are about the differences.
My experience is that all the languages are identical. Python has a culture of cleanliness at the core, but there is a lot missing from the language that makes it unclean in practices. (See: the investment bank I worked where all new apps were written in a C#/C++/Python trialect, to coin a new word.) Perl is a very messy language, but the community has hyper-overreacted and have made a very clean set of "best practices". I haven't done much Ruby, but I can't say anything other than that it looks like a combination of Perl and Python, with a relatively new community around it.
These three languages are largely the same thing: they run slow and they're fun to write. Hence all the infighting.
Honestly, I think that the reason is simple: because it's entertaining. Yeah, sometimes I'm tired of reading the same arguments over, and over, and over again. But sometimes, an OP is particularly eloquent in his trashing a language, and I like that, even if the language he's trashing is my favorite.
The same goes with rants. I can't understand people debating over Linus Torvalds rant on C++. Honestly, I found it hilarious and well written. That's it, I'm looking no further because I know that this type of argument has no end.
I would certainly not care to debate the relative merit of my favorite language in one of those troll topics, but I do enjoy reading heated programmers exercising their writing skills against each other.
But ignoring that; someone who is new to programming is not going to understand the value of any of these concepts anyway, so it doesn't matter that they don't discover them immediately. At about the same time people figure out how to do OO cleanly, they will start hearing about libraries too.
If you were to navigate a largish Perl codebase today, you'd encounter the old-school bless, Moose trickiness, and all kinds of variants on these themes. Extremely clever stuff that Damian Conway would give you a gold star for.
I've worked on a number of post-Moose codebases, and most people did the conversion cleanly and all at once. (I can't explain it, I'm just reporting the facts. I was surprised too.) The biggest Moose-hacking pain point I've seen was someone trying to subclass DateTime with Moose. It just doesn't work very well; DateTime is werid and Moose is weird. (Of course, the solution is delegation rather than subclassing. Even in languages with real OO, you often want a "does X interface by delegating to Y class" rather than "isa Y".)
Both projects suck equally. The python project is much newer (~4 years instead of 12), but the smell is about the same. The problem with new programmers isn't that they pick the wrong object creation patterns, but that they reinvent the wheel and write long stupid functions with horrible nested if/else statements. A former google employee worked on one of the projects, and wrote her own python to json function.
I like python, and I like perl, but the python culture sucks. It has this weird superiority complex where it rejects any external ideas. If I am talking to perl people, and I mention some kick ass python feature that I miss, I either get information as to how it can be done in perl, or interest into why I like it. Around python people, I generally get something like, "well, none of us know perl. Have you tried doing it the python way?"
Moose is awesome, perlbrew is awesome, perl's module culture is awesome. The module culture is the one that annoys me most often. Python programmers don't write as good of tests, or nearly as good of documentation. We still have to run a lot of python 2.4, and a lot of modules claim 2.4 support and then use 2.6+ syntax.
I like python, I think it is a much better matlab, but a lot of its syntax is unintuitive and stupid, and there are some serious cultural issues. Anyone who thinks that it is perfect, or better than another language in every way is holding it back.
$a = array(1,2,array(3,4));
$a = [1,2,[3,4]];
0b101010
> no reason for anyone really not to have adopted it.
These things are not mutually exclusive. I.e. you could be write, but Klinky definitely is.
Thanks for sharing, ill pass it on whenever a comparison is needed.
$array = [1, 2, 3];
I mean Wordpress flat out resisted PHP 5.0 for years. Years. Everything had to be done in PHP4.
I presume that's because of the size of Wordpress' install base. The number of people who run their software on $9/month shared hosting environments is staggering. Many of those are late to upgrade PHP versions.
Wordpress gets a lot of crap for being poorly written but the truth is that it's an example of software that works really well given some really unique circumstances. If the WP devs decided that their software didn't need to support the 99% of web servers out there then it wouldn't be nearly as ubiquitous as it is today.
Yes, they deal with lots of different configurations. This is not unique in the history of software development. It's called "portability" and many organisations seem to be able to achieve it without compromising quality.
My searing, eye-boiling hatred for Wordpress comes from administering it for what is now nearly a decade. Every time I dive into the code I am frequently repulsed by it.
The total absence of tests is my favourite "feature". I've seen multiple bugs closed with WORKSFORME that I was directly grappling with.
Wordpress delivers these in spades.
The only exceptions for me have been when I've had to deal with someone else's codebase, or with Wordpress (and Django once), but again, I wouldn't personally take a job where those were the main responsibilities.
Some examples:
Null test:
$var === null // omitted
isset($var) // actually checks if $var exists and is not null (apparently--
I actually didn't know about the not null part)
Add time duration
strtotime('+10 minutes') is more typical than the objects
def foo s
s.concat 'foo'
end
a = 'bar'
foo a
a
# => "barfoo"They both do "pass reference by value". Which is a big difference.
def foo s
s = 'foo'
end
a = 'bar'
foo a
puts a
# => bar
For more examples and explanation, see http://khelll.com/blog/ruby/ruby-pass-by-value-or-by-referen...
class Fixnum
alias :realplus :+
def + b
@a ||= 0
@a = @a.realplus(b)
self.realplus(@a)
end
end
Of course all hell will break loose and adding instance variables in certain classes like Fixnum will be extra slow (as if there aren't enough other reasons not to), since MRI uses type-tagging for Fixnum, Symbol and a few others, and so since they're not "real" objects, if you do anything that requires one, it creates one that's stored in a hash table.
awk begat perl.
perl begat python and ruby.
python will get you a job at google.
ruby will get you a job at twitter.
php will get you a job at facebook.
I used Perl for all of my job interviews at Google, and I work at Google.
But Google is a Java and C++ company, with some Python around (but a bit of an anti-scripting culture as well).
I heard that twitter are moving from ruby to scala.
Edit: Found Lua compared on the same site here: http://hyperpolyglot.org/embeddable
If you really want a repl that's useful for PHP check out http://www.phpsh.org/ by Facebook.
x += 1
x -= 1
He never even uses Perl's foreach in equivalency examples!! WTF.
Also, you can report bugs on the table if things are not correct.
Empty comments can be ok if they're positive. There's
nothing wrong with submitting a comment saying just
"Thanks." What we especially discourage are comments that
are empty and negative—comments that are mere name-calling.
A suggestion: For people doing some work in Perl, a review of the OO syntax might be critical. Both Moose and the old way.
A note, re the repl part: I don't use a repl for Perl, I just write one liners in shell. Afaik, Perl is the best command line tool that exist, it is even a superset of awk.
Edit: For named parameters the page might want to reference one of the CPAN modules doing that. Same goes for exceptions. The use of do to create blocks most everywhere might also be noted in e.g. the ternary operator. Unicode support should probably also be discussed. And so on.
These languages are essentially the same thing. I often write code in at least 3 of these languages most days, and I simply translate the minor differences between them in my head.
"Hyperpolyglot" -- excess in many tongues -- I don't think so.
Learn at least some static languages, assembler and some functional languages, and then post something interesting on HN.
Well, I have plenty of karma to waste on noobs.