Keywords, &blocks and instance_eval

ruby-talk
1

Hi

I am fine tuning a DSL and came across the situation
where I needed a method with the name of 'module'.

In my previous revision of the DSL, I did the following:

···

------------
  class C
    def initialize
      yield self
    end
    def module
      puts "in C#module"
    end
  end
-------------

The user code would then look like:

  C.new do |c|
    c.module
  end

But, I didn't really like requiring (or explaining)
why the 'c.' was required. So I rewrote the class to be:

------------
  class C
    def initialize(&block)
      instance_eval &block
    end
    def module
      puts "in C#module"
    end
  end
-------------

But, when a method name is called that is dear to Ruby heart,
like 'module', an error is generated:

  C.new do
    module
  end #=> syntax error

Is there any way to have get the effect of the above

c.module

with the instance_eval?

Thanks
--
Jim Freeze

2

Jim Freeze wrote:

Hi

I am fine tuning a DSL and came across the situation
where I needed a method with the name of 'module'.

In my previous revision of the DSL, I did the following:

------------
  class C
    def initialize
      yield self
    end
    def module
      puts "in C#module"
    end
  end
-------------

The user code would then look like:

  C.new do |c|
    c.module
  end

But, I didn't really like requiring (or explaining)
why the 'c.' was required. So I rewrote the class to be:

------------
  class C
    def initialize(&block)
      instance_eval &block
    end
    def module
      puts "in C#module"
    end
  end
-------------

But, when a method name is called that is dear to Ruby heart,
like 'module', an error is generated:

  C.new do
    module
  end #=> syntax error

Is there any way to have get the effect of the above

c.module

with the instance_eval?

No. Unless you resort to using string instead of a block and do some
gsub'bing on the string which inserts the "c." part (or "self." in that
case).

"module" and "class" are keywords. That's why you never can do
"class.new..." but always have to "self.class.new...".

Kind regards

    robert