Affect of CAREFULLY on MYSELF

[James Steiner]

I was trying something unusual, and *just* noticed that MYSELF has an unexpected (to me)  behavior when used inside a CAREFULLY block, and this behavior is not called out in the Primitives Dictionary. Maybe one of the NetLogo books mentions it.

It seems that NetLogo CAREFULLY creates a new "inner" agent execution context, so that MYSELF points to "the agent that asked this agent to run this code", or in other words, the same agent running CAREFULLY

Here is the output of a test:

observer> test-myself
(patch -24 -14): "self is(patch -24 -14)"
(patch -24 -14): "carefully myself is (patch -24 -14)" (Note: I THINK THIS SHOULD THROW AN ERROR, IT DOESN'T)
(turtle 0): "self is(turtle 0)"
(turtle 0): "myself is (patch -24 -14)"
(turtle 0): "carefully myself is (turtle 0)"
(turtle 1): "self is(turtle 1)"
(turtle 1): "myself is (turtle 0)"
(turtle 1): "carefully myself is (turtle 1)"
(link 0 1): "self is(link 0 1)"
(link 0 1): "myself is (turtle 1)"
(link 0 1): "carefully myself is (link 0 1)"

Here is the code of that test:

to id
  show (word "self is" self)
end

to id-myself
  let $myself "undefined"
  set $myself myself
  show (word "myself is " $myself)
end

to id-myself-carefully
  let $myself "undefined"
  carefully [ set $myself myself ][]
  ;; running in the observer context, I think this should throw an error

  ;; leaving $myself with a value of "undefined." It doesn't.
  show (word "carefully myself is " $myself)
end

to test-myself
  clear-all
  ask patch min-pxcor min-pycor
  [ id
    id-myself-carefully
    sprout 1
    [ id
      id-myself
      id-myself-carefully
      hatch 1
      [ id
        id-myself
        id-myself-carefully
        create-link-with myself
        [ id
          id-myself
          id-myself-carefully
        ]
      ]
    ]
  ]  
end

Thoughts?