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What's better about Ruby than Python? - comp.lang.python

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Re: What's better about Ruby than Python? - comp.lang.python

#11

Post by cameldrv »

wrs wrote: post #8

This is good stuff, except that he seems to misunderstand the ()-less method call in Ruby. There's no "function" or "object" being "called" with that syntax, as in Pascal or Visual Basic (his chosen analogies). There are no functions in Ruby in that sense, and callable objects are explicitly called (with a "call" method). The expression "foo" in Ruby evaluates to the value of the local variable "foo" if any, or else…

Yes, there is a semantic difference here. In Python, you can do things like this:

  if baz>10:
      func = self.foo
  else:
      func = self.bar
  result = func()
Here func gets assigned something called a "bound method", which has a reference to the object and the method, which you can then apply the () operator and call. I am not a rubyist, but my understanding is that you would use a symbol to do a similar thing.

Re: What's better about Ruby than Python? - comp.lang.python

#13

Post by ionrock »

wrs wrote: post #8

This is good stuff, except that he seems to misunderstand the ()-less method call in Ruby. There's no "function" or "object" being "called" with that syntax, as in Pascal or Visual Basic (his chosen analogies). There are no functions in Ruby in that sense, and callable objects are explicitly called (with a "call" method). The expression "foo" in Ruby evaluates to the value of the local variable "foo" if any, or else…

I like your perspective on this design decision as it seems to make clear what the intent could be. Alex reveals that the difference in Python is not so much the syntax as much as it hints at Python's treatment of functions as first class objects. This is really similar to Javascript where you can pass functions around for later evaluation. It adds a different level of complexity, of course, but it is something that I have appreciated in Python a great deal.

Re: What's better about Ruby than Python? - comp.lang.python

#14

Post by rlivsey »

cameldrv wrote: post #11
wrs wrote: post #8

This is good stuff, except that he seems to misunderstand the ()-less method call in Ruby. There's no "function" or "object" being "called" with that syntax, as in Pascal or Visual Basic (his chosen analogies). There are no functions in Ruby in that sense, and callable objects are explicitly called (with a "call" method). The expression "foo" in Ruby evaluates to the value of the local variable "foo" if any, or else…

Yes, there is a semantic difference here. In Python, you can do things like this: if baz>10: func = self.foo else: func = self.bar result = func() Here func gets assigned something called a "bound method", which has a reference to the object and the method, which you can then apply the () operator and call. I am not a rubyist, but my understanding is that you would use a symbol to do a similar thing.

Yep, the equivalent would probably be something along the lines of:

    if baz > 10
      func = :foo
    else
      func = :bar
    end

    result = self.send(func)

Re: What's better about Ruby than Python? - comp.lang.python

#15

Post by DanielRibeiro »

telemachos wrote: post #2

The title made me nervous that this would be run-of-the-mill fanboy garbage. But I trust the author (Alex Martelli), so I read it, and I'm glad I did. It's reasonable and sane. My two big take-away points: 1) It's very nearly a wash. Ruby and Python are so close together (beneath any superficial differences) that distinguishing is almost an exercise in futility. 2) The key thing about Ruby he doesn't like is its "TOT…

About point 2: the author is probably ignorant of ast module (http://docs.python.org/library/ast.html), which allows the programmer to take any ast and recompile it to anything he/she wants (in runtime, unlike Lisp macros, but alike parse tree and ruby2ruby in ruby).

This feature allows you to transform things like "1, minute" into "Minute(1)", enabling dsls, and "wrecking havoc" all over. In ruby, you don't have to do this, as there are simpler and less powerful metaprogramming tools.

So yeah. Just because you have a shotgun, it doesn't mean you can't use it to kill a fly. Of course, the really important question is not if you can, but if you should. And it is always better that this decision is left for the users of the language than to its creators.

Re: What's better about Ruby than Python? - comp.lang.python

#16

Post by jshen »

cageface wrote: post #9
telemachos wrote: post #2

The title made me nervous that this would be run-of-the-mill fanboy garbage. But I trust the author (Alex Martelli), so I read it, and I'm glad I did. It's reasonable and sane. My two big take-away points: 1) It's very nearly a wash. Ruby and Python are so close together (beneath any superficial differences) that distinguishing is almost an exercise in futility. 2) The key thing about Ruby he doesn't like is its "TOT…

Both languages offer the unvigilant programmer plenty of opportuities to shoot off his foot. If you're really concerned about this you should take a look at scala. I'm amazed at how much easier it is for me to maintain my own scala code than either ruby or python.

and so much harder for me to maintain someone else's scala code. It feels like statically typed perl, but that's just mho.

Re: What's better about Ruby than Python? - comp.lang.python

#17

Post by jshen »

rjurney wrote: post #4
telemachos wrote: post #2

The title made me nervous that this would be run-of-the-mill fanboy garbage. But I trust the author (Alex Martelli), so I read it, and I'm glad I did. It's reasonable and sane. My two big take-away points: 1) It's very nearly a wash. Ruby and Python are so close together (beneath any superficial differences) that distinguishing is almost an exercise in futility. 2) The key thing about Ruby he doesn't like is its "TOT…

The fact that anyone at any point can monkey patch any built-in is a potential liability for large teams, with average programmers. It must be addressed by culture and code review that you may or may not have. Still worth it though :)

I've never bought the idea that the opposite is a better trade off because it comes with costs too. Have you ever worked with a bunch of mediocre java programers? Heaven forbid they make an interface that isn't well thought out and needs to be changed later!

Re: What's better about Ruby than Python? - comp.lang.python

#18

Post by msbarnett »

cameldrv wrote: post #11
wrs wrote: post #8

This is good stuff, except that he seems to misunderstand the ()-less method call in Ruby. There's no "function" or "object" being "called" with that syntax, as in Pascal or Visual Basic (his chosen analogies). There are no functions in Ruby in that sense, and callable objects are explicitly called (with a "call" method). The expression "foo" in Ruby evaluates to the value of the local variable "foo" if any, or else…

Yes, there is a semantic difference here. In Python, you can do things like this: if baz>10: func = self.foo else: func = self.bar result = func() Here func gets assigned something called a "bound method", which has a reference to the object and the method, which you can then apply the () operator and call. I am not a rubyist, but my understanding is that you would use a symbol to do a similar thing.

You certainly could solve that with a symbol, I suppose, but that's a bit like doing a word-for-word translation of 'it's raining cats and dogs' into a foreign language. Better to translate to the local idiom than to try to blindly write Fortran in any language, as the saying goes.

So, for instance, you might solve it with:

  result = case
    when baz>10 then foo
    else bar
  end
This is synthetic, of course. If the goal is to pass around methods, there are lambdas and codeblocks that can be passed around and may fit the problem more naturally than sending yourself a symbol as a message.

Re: What's better about Ruby than Python? - comp.lang.python

#19

Post by sandal »

rlivsey wrote: post #14
cameldrv wrote: post #11

Earlier quoted context omitted.

Yes, there is a semantic difference here. In Python, you can do things like this: if baz>10: func = self.foo else: func = self.bar result = func() Here func gets assigned something called a "bound method", which has a reference to the object and the method, which you can then apply the () operator and call. I am not a rubyist, but my understanding is that you would use a symbol to do a similar thing.

Yep, the equivalent would probably be something along the lines of: if baz > 10 func = :foo else func = :bar end result = self.send(func)

That may accomplish the same thing, but the direct translation would be:

    if baz > 10
       func = method(:foo)
    else
       func = method(:bar)
    end
 
    result = func.call
Here, we actually deal with the Method objects, rather than just sending a dynamic message. Although the send() approach would be closer to idiomatic Ruby, I wanted to emphasize that dealing with methods as first class objects in Ruby is indeed possible.

Re: What's better about Ruby than Python? - comp.lang.python

#20

Post by rjurney »

jshen wrote: post #17
rjurney wrote: post #4

Earlier quoted context omitted.

The fact that anyone at any point can monkey patch any built-in is a potential liability for large teams, with average programmers. It must be addressed by culture and code review that you may or may not have. Still worth it though :)

I've never bought the idea that the opposite is a better trade off because it comes with costs too. Have you ever worked with a bunch of mediocre java programers? Heaven forbid they make an interface that isn't well thought out and needs to be changed later!

That extreme is also terrible. Python is somewhere in between.
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