Comment by zwp | Hacker News Reader

Comment by zwp | Hacker News Reader

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So the functionality is equivalent, but ruby's syntax is slightly longer. Is there something other than ruby's slightly longer syntax that you find lacking?

Ruby's Method class matches the design "everything is an object" (strings, numbers, modules & classes themselves...). Are regular expressions first class in ruby? There is top-level syntactic sugar for REs (/.../) but REs are just instances of `Regexp`. It's just syntax. I don't think you can argue Python REs are first class: I have to drag in `re` and then `re.compile()` a string (and my editor won't know to syntax highlight metachars or interpolation). I use REs more often than method references in either language...

But I'm not trying to "whataboutwhataboutwhatabout" here. I'm trying to say there's a difference of philosophy. Ruby Methods are just more objects (Method<Object). They aren't some sort of blessed type, just like everything else. Everything descends from Object. Kernel is just a module. Method is just a class. And so on. In that context, what does it mean to be "first class"? Objects are first class and methods are objects. QED. No?

(FWIW I agree on ruby's optional parens, too much inconsistency for a few less lit pixels on the screen).

> In that context, what does it mean to be "first class"

It's easy. First, what does it mean to be "first class"?

> a first-class citizen (also type, object, entity, or value) in a given programming language is an entity which supports all the operations generally available to other entities. These operations typically include being passed as an argument, returned from a function, modified, and assigned to a variable

Secondly, how does that apply to functions?

> [First class functions] means the language supports passing functions as arguments to other functions, returning them as the values from other functions, and assigning them to variables or storing them in data structures

In what way doesn't Ruby have first class functions? This article explains it better: https://codequizzes.wordpress.com/2014/05/19/ruby-methods-ar...

In practice, because of Proc, you can use Proc wherever you'd use functions and get the same effect in practice, so this is not a big issue. But just because Ruby has Procs, doesn't mean it has first class functions, which is a specific concept.

Thanks, I had also looked for a definition. Instances of Method fulfill both of the cited criteria -- example in this thread, above. Also: Method != Proc, but the article's comments help.

I, aha, notice this:

    $ irb
    2.3.3 :001 > Kernel.method(:puts).object_id
     => 47165335040720 
    2.3.3 :002 > Kernel.method(:puts).object_id
     => 47165334993360 # not the same!
    2.3.3 :003 >

That is: #method doesn't return the Kernel.puts method, it returns a new Kernel.puts Method instance on each invocation. So the returned object from Kernel#method isn't the "real" (first-class) method object.

I feel like I'm a lot closer but I'd still like a better definition :)

Isn't the main issue that Ruby simply doesn't have functions? Ruby is pure OOP, and there is no way to define a method without the implicit 'self' argument. Maybe the reasoning was that methods themselves aren't really meant to be passed around. Because in today's idiomatic Ruby, they mostly aren't -- the late binding behavior of 'send' feels much more Rubyish.

Exactly. And Ruby methods are not even "functions with self" they are message-handlers. Like in Smalltalk or Objective-C.

Different heritage

Sorry, Ruby methods are not objects. They can surely be wrapped in objects of class Method, but this feature is used quite rarely. Whether this is due to the syntax, the confusion regarding the evaluation scope, or something else, I have no idea.

The only way of obtaining a method in Ruby returns it as an object. Whether or not they "are" an object is thus entirely an implementation detail.

I think part of the confuction here is that "ob.puts" for example, does not directly access a method. It denotes passing a message to "ob". That message may or may not be routed to a "puts" method.

But at no point does Ruby allow you to get hold of any kind of reference to a method that is anything but an object.

Yeah, you got it, see my reply to capableweb. Thanks!

> and my editor won't know to syntax highlight metachars or interpolation

IntelliJ editors do this and it’s insanely useful. Works with SQL, regex and any other language.

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