class arrays

[poseid]

Hello,

how does this work?

class A
b = [1, 2,3]
end => [1, 2, 3]

Is b an instance variable? class variable? how would I access b from
outside the class?

thanks

 

[MrZombie]

Hello,

how does this work?

thanks

Erh, not that way. Sorry.

You could have

class A
@b = [1,2,3]
end

Which stores the array in a class-level instance variable.

This other one
class A
@@b = [1,2,3]
end

stores the array in a class variable.

An instance variable would (or could, anyway) be used like this

class A
def initialize
@b = [1,2,3]
end

#accessor methods
def b
@b
end
def b= (value)
@b = value
end
end

Also, you can shorten the accessor methods to

class A
attr_accessor :b
def initialize
@b = [1,2,3]
end
end

 

[poseid]

Erh, not that way. Sorry.

You could have

class A
 @b = [1,2,3]
end

Which stores the array in a class-level instance variable.

This other one
class A
 @@b = [1,2,3]
end

stores the array in a class variable.

Hm... ok, this is more or less what I expected as well, when reading
code employing instance/class variables. But how do I understand the
(old) code from a book on Rails:

class T < ActionView::Helpers::FormBuilder
field_helpers.each do |s|
src = <<-END_SRC
def #{s}(field, options = {})
@template.content_tag( ... )
end
END_SRC
class_eval src, __FILE__, __LINE__
end
end

To me it seems that field_helpers is an instance variable, but there
is no @ nor @@ used

thanks for feedback

 

[poseid]

Erh, not that way. Sorry.

You could have

class A
 @b = [1,2,3]
end

Which stores the array in a class-level instance variable.

This other one
class A
 @@b = [1,2,3]
end

stores the array in a class variable.

Hm... ok, this is more or less what I expected as well, when reading
code employing instance/class variables. But how do I understand the
(old) code from a book on Rails:

class T < ActionView::Helpers::FormBuilder
field_helpers.each do |s|
src = <<-END_SRC
def #{s}(field, options = {})
@template.content_tag( ... )
end
END_SRC
class_eval src, __FILE__, __LINE__
end
end

To me it seems that field_helpers is an instance variable, but there
is no @ nor @@ used

thanks for feedback