def exec_in_proxy_context(dsl, proxy_type, *args, &block)
block_context = eval('self', block.binding)
proxy_context = proxy_type.new(dsl, block_context)
begin
block_context.instance_variables.each do |ivar|
value_from_block = block_context.instance_variable_get(ivar)
proxy_context.instance_variable_set(ivar, value_from_block)
end
proxy_context.instance_exec(*args, &block)
ensure
block_context.instance_variables.each do |ivar|
value_from_dsl_proxy = proxy_context.instance_variable_get(ivar)
block_context.instance_variable_set(ivar, value_from_dsl_proxy)
end
end
end