Rbx bytecode helpers - draft

show_stack.rb

class Rubinius::Generator
  # Shows the topmost element on the stack and the stack's current size.
  #
  # Calling #show_stack neither consumes nor produces stack, it's just used
  # for debugging the current state.
  #
  # @param [String] name an optional label to print out, to make debugging
  #   easier.
  #
  def show_stack(name = nil)
    size = @current_block.instance_eval { @stack }

    dup
    push :self
    swap_stack
    send :inspect, 0, true
    push_literal "[#{name || 'DEBUG'}] [STACK SIZE: #{size}]: "
    swap_stack
    push_literal "\n"
    send :print, 3, true 
    pop
  end
end

class Foo
  dynamic_method :bar do |g|
    g.push :self
    g.push_literal "hello"
    g.show_stack 'just after pushed literal hello'
    g.send :puts, 1, true
    g.show_stack 'this should be nil and the stack size should be 1'
    g.ret
  end
end

Foo.new.bar

# prints:
# 
# [just after pushed literal hello] [STACK SIZE: 2]: "hello"
# hello
# [this should be nil and the stack size should be 1] [STACK SIZE: 1]: nil