rubyx/lib/parfait/frame.rb

# A Frame is set up by functions that use local variables or temporary variables
# in fact temporary variables are local variables named by the system

# It allows for access to those variables basically

# A Message and a Frame make up the two sides of message passing:
# A Message (see details there) is created by the sender and control is transferred
# A Frame is created by the receiver
# PS: it turns out that both messages and frames are created at compile, not run-time, and
#  just constantly reused. Each message has a frame object ready and ist also linked
#  to the next message.
# The better way to say above is that a messages is *used* by the caller, and a frame by the callee.

# In static languages these two objects are one, because the method is known at compile time.
# In that case the whole frame is usually on the stack, for leaves even omitted and all data is
#  held in registers
#
# In a dynamic language the method is dynamically resolved, and so the size of the frame is not
# know to the caller
# Also exceptions (with the possibility of retry) and the idea of being able to take and store
# bindings make it, to say the very least, unsensibly tricky to store them on the stack. So we don't.

# Also at runtime Messages and Frames remain completely "normal" objects. Ie have layouts and so on.
# Which resolves the dichotomy of objects on the stack or heap. Sama sama.

module Parfait
  class Frame < Object
    attribute :next_frame

    def self.offset
      1 + Space.object_space.get_class_by_name(:Frame).object_layout.object_instance_length
    end

  end
end