Discussion: duality between instance variables and attribute methods

[hachi8833]

As you know, Ruby's #= methods from attr_accessor or attr_writer are pretty confusing when assigning:

class Foo
  attr_accessor :bar, :baz, :bud
  def initialize
    bar = "hoge"         # just creates a new local variable `bar`
    self.baz = "huga"    # needs a receiver  `self.` to get `#=` work
    @bud = "huge"        # works
  end
end

Foo.new.bar
#» nil
Foo.new.baz
#» huga
Foo.new.bud
#» huge

Essentially, Ruby has a duality: you sometime call the ones "instance variables" and sometime "attributes".

Goby behaviors the same as above for now.

I hope Goby could provide a syntax level solution for that. Which of the following is preferable?

• A: Prioritize the implicit receiver self. within a class
  • bar = is equivalent to self.bar in the class
• B: Warn when an instance method has been defined and trying to assign to a variable with the same name
  • attr_accessor :bar and then bar = "hoge" within the class prints "Warning: you are trying to create a variable with the same name as an instance variable."
• C: Disable accessor methods only within the class
  • You should always use @ to access instance variables in the case.
  • Attribute accessors are only for external use.
  • If possible, change the attr_* syntax to attr_accessor @bar, @baz or like that to indicate that it actually creates instance variables.
• etc.

Personally I prefer to C, next B because A still have an ambiguity among @bar and #bar and bar for internal use:

class Foo
  attr_accessor :bar
  def initialize
    @bar = "hoge"
  end
  def show
    puts bar      # reading @bar via `#bar`, which apparently looks reading a local variable
    puts @bar     # I feel this is preferable
  end
end

Foo.new.show
#=> hoge
#=> hoge

B is less excessive and would be nice for Ruby.

Any suggestions?

[64kramsystem]

Assuming this would be implemented, I'd personally prefer a warning. Definitely not A, which wouldn't solve the ambiguity problem.

[st0012]

@hachi8833 this could be scanned by linter I think

[hachi8833]

I'm changing my mind around this: I'd close this issue, ok?