Dumb question: in documentation, why Object#method, and not Object.method ?

[Elf M. Sternberg]

I keep seeing this syntax in documentation: Object#method, but in actual
use sending a message to an object is usually

object = Object.new
object.method

Is this just to emphasize that method() operates on an instance of
Object and not the class Object?

Elf

 

[Bob Showalter]

I keep seeing this syntax in documentation: Object#method, but in actual
use sending a message to an object is usually

object = Object.new
object.method

Is this just to emphasize that method() operates on an instance of
Object and not the class Object?

Yes.

 

[Jeffrey Schwab]

I keep seeing this syntax in documentation: Object#method, but in actual
use sending a message to an object is usually

object = Object.new
object.method

Is this just to emphasize that method() operates on an instance of
Object and not the class Object?

Yes.

 

[Trans]

Yes. ;-)

 

[Austin Ziegler]

I keep seeing this syntax in documentation: Object#method, but in actual
use sending a message to an object is usually

object =3D Object.new
object.method

Is this just to emphasize that method() operates on an instance of
Object and not the class Object?

As others have said, yes. As I understand it, though, it's a smalltalkism.

-austin

 

[Trans]

Notice that "Object" in "Object#method" is capitalized. We're talking
about a class here not an instance. So if you were to say Object.method
you'd be refering to an instance method of the class itself --generally
called a _class method_, as opposed to an instance method defined by
the class. It's tricky because its relative --a class is itself an
instance of Class.

HTH,
T.

 

[David A. Black]

Hi --

The # is a naming convention.

Class#method means method is an instance method.
Class::method means method is a class method.

For example, do

ri IO.read

There is IO::read and IO#read.

Interesting -- I never picked up on ri's use of :: in preference to
the dot. I personally use Class.method for class methods (indeed for
any singleton method).


David

 

[Daniel Schierbeck]

Hi --



Interesting -- I never picked up on ri's use of :: in preference to
the dot. I personally use Class.method for class methods (indeed for
any singleton method).

I believe that to be the convention, too.

Klass.method <- Class method
Klass#method <- Instance method
Klass::FOO <- Class constant
Klass::AnotherKlass <- Class constant (class or module)

 

[jwesley]

Hmm...so Class is an instance of itself?

 

[MenTaLguY]

--=-q8vfd9xedR+DKdFV5gsp
Content-Type: text/plain
Content-Transfer-Encoding: quoted-printable

Hmm...so Class is an instance of itself?

Yep.

Class.class # =3D> Class

-mental

--=-q8vfd9xedR+DKdFV5gsp
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Content-Description: This is a digitally signed message part

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--=-q8vfd9xedR+DKdFV5gsp--

 

[David A. Black]

Hi --

Hmm...so Class is an instance of itself?

Yes. And Object is a Class, and Class is an Object Ruby
object-space chases its own tail a bit at the top of the hierarchy,
for the sake of bootstrapping itself into existence.


David

 

[Gary Leydon]

I keep seeing this syntax in documentation: Object#method, but in actual
use sending a message to an object is usually

object = Object.new
object.method

Is this just to emphasize that method() operates on an instance of
Object and not the class Object?

Elf

Where is this documented? I can't find it in any book...and searching
google on Ruby object#method doesn't lead to an explanation of this. You
get reams of hits using object#method syntax but not where it comes
from.

 

[James Coglan]

[Note: parts of this message were removed to make it a legal post.]

Where is this documented? I can't find it in any book...and searching
google on Ruby object#method doesn't lead to an explanation of this. You
get reams of hits using object#method syntax but not where it comes
from.

http://ruby-doc.org/core/classes/Object.html#M000336

 

[Codeblogger]

Where is this documented? I can't find it in any book...and searching
google on Ruby object#method doesn't lead to an explanation of this.

I immediately found it on ruby-doc.org:
http://www.ruby-doc.org/core/classes/Object.html#M000336

Regards
Nicolai

 

[gb le]

I immediately found it on ruby-doc.org:
http://www.ruby-doc.org/core/classes/Object.html#M000336

Regards
Nicolai

Thanks for taking the time, I suspect I didn't make my question
clear,there is nothing that I can see on the link Object.html#M000336
that specifies what object#method means vs object::method but your link
lead me to search on the site and I found it here
http://ruby-doc.org/documentation-guidelines.html, somewhat buried but
certainly clear.

Style Guidelines

Use :: for describing class methods,
# for describing instance methods,
. for example code.

 

[Matthias Reitinger]

Where is this documented? I can't find it in any book...and searching
google on Ruby object#method doesn't lead to an explanation of this. You
get reams of hits using object#method syntax but not where it comes
from.

The 1st edition of "Programming Ruby"[1] (a.k.a. the "Pickaxe") mentions
this notation:

Within the text, Fred#doIt is a reference to an instance method (doIt) of
class Fred, while Fred.new [In some other Ruby documentation, you may
see class methods written as Fred::new. This is perfectly valid Ruby
syntax; we just happen to feel that Fred.new is less distracting to
read.] is a class method, and Fred::EOF is a class constant.

The first appearance in the Ruby changelog[2] dates back to 1995,
suggesting that Matz himself may have introduced this convention.

-Matthias

[1]: http://www.rubycentral.com/pickaxe/preface.html
[2]:
http://svn.ruby-lang.org/cgi-bin/viewvc.cgi/tags/v1_0/ChangeLog?revision=2&view=markup