Question

I have a Builder class that lets you add to one of it’s instance variables:

class Builder
    def initialize
        @lines = []
    end

    def lines
        block_given? ? yield(self) : @lines
    end

    def add_line( text )
        @lines << text
    end
end

Now, how do I change this

my_builder = Builder.new
my_builder.lines { |b|
    b.add_line "foo"
    b.add_line "bar"
}
p my_builder.lines # => ["foo", "bar"]

Into this?

my_builder = Builder.new
my_builder.lines {
    add_line "foo"
    add_line "bar"
}
p my_builder.lines # => ["foo", "bar"]

Answer 1

class Builder
    def initialize
        @lines = []
    end

    def lines(&block)
        block_given? ? instance_eval(&block) : @lines
    end

    def add_line( text )
        @lines << text
    end
end

my_builder = Builder.new
my_builder.lines {
    add_line "foo"
    add_line "bar"
}
p my_builder.lines # => ["foo", "bar"]