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comp.lang.ruby

What's the difference in calling method vs self.method?

Jim

12/31/2005 6:43:00 PM

Here's some example code. In method_b, what is the difference in
calling method_a and self.method_a?


class HoHo

def method_a
puts "Hello, HoHo"
end

def method_b
method_a
self.method_a
end

end

hoho = HoHo.new
hoho.method_b
5 Answers

Tool69

12/31/2005 6:54:00 PM

0

I see no difference indeed, but I'm a Ruby beginner...This is a Ruby
shortcut I think, all method calls inside a class are supposed to be
applied to the called "self" object. Maybe to avoid some "heavy" Python
syntax in wich you'll always see "this.method".
Am I wrong ?

Joseph Divelbiss

12/31/2005 6:58:00 PM

0

Jim wrote:
> Here's some example code. In method_b, what is the difference in
> calling method_a and self.method_a?
>

I am sure that the more experienced coders will speak up soon, but until
then Ill do my best.

The self. is implied when you call the method..
just as self.puts or self.gets are often written puts or gets
respectively..

Hope that makes sense.

--
Posted via http://www.ruby-....

Jim

12/31/2005 7:07:00 PM

0


Jim wrote:
> Here's some example code. In method_b, what is the difference in
> calling method_a and self.method_a?

I just had a thought that it may very well make a difference in the
case of a conflict method names. For example if you had (puposely or
not) created 2 method_a's in the same scope. Make sense?

Marcin Mielzynski

12/31/2005 7:12:00 PM

0

Jim wrote:
> Here's some example code. In method_b, what is the difference in
> calling method_a and self.method_a?
>

In Your code it makes no difference, however there are situations when
You'll have to explicitly resolve method invocation, consider:

class C
def meth1
end

def meth2
meth1 # no problem, but..
meth1=4 # variable assignment
self.meth1 # so we have to resolve it as a method
end
end

other thing is operator method invocation:

class D

def + arg
p arg
end

def meth
+ 2 # Ruby sees it as unary plus, aka +@
self + 2 # explicit
end

end


lopex

Ross Bamford

12/31/2005 7:50:00 PM

0

On Sat, 31 Dec 2005 19:11:37 -0000, Marcin MielżyÅ?ski <lopexx@autograf.pl>
wrote:

> Jim wrote:
>> Here's some example code. In method_b, what is the difference in
>> calling method_a and self.method_a?
>>
>
> In Your code it makes no difference, however there are situations when
> You'll have to explicitly resolve method invocation, consider:
>
> class C
> def meth1
> end
>
> def meth2
> meth1 # no problem, but..
> meth1=4 # variable assignment
> self.meth1 # so we have to resolve it as a method
> end
> end
>
> other thing is operator method invocation:
>
> class D
>
> def + arg
> p arg
> end
>
> def meth
> + 2 # Ruby sees it as unary plus, aka +@
> self + 2 # explicit
> end
>
> end
>
>

Somewhat related to the above is the following case:

class Clz
attr_accessor :myattr

def amethod
# doesn't work, Ruby treats as local assignment
# myattr = 5

# We have to be explicit.
self.myattr = 5
end
end

Another area I guess it could make a difference is:

class ClzToo

def amethod
# doesn't work, private methods cannot be called
# with a receiver.
# puts self.aprivate

# So we can only call without 'self'
puts aprivate
end

private

def aprivate
"private"
end
end


--
Ross Bamford - rosco@roscopeco.remove.co.uk