testible.clef means look up the value stored at what clef evaluates to in testible

testible!clef means look up the value stored at clef in testible

testable.0 means look up the value stored (at what 0 evaluates to) in testible

testible!0 means look up the value stored at 0 in testible

atist.0 means look up the value stored at what 0 evaluates to in atist

atist!0 means look up the value stored at 0 in atist

0 of course being an atom evaluates to 0

but what if you want it to evalute to something like the key stored at 0 . . . . . . if quote means something like "don't evaluate" and unquote means something like "do evaluate" then one could reason that atist,0 means look up the value stored at what 0 evaluates to (do evaluate it) in atist

  arc> atist.0
    '(a "up")
  
  arc> atist!0
    '(a "up")
  
  arc> atist,0
    "up"

Is this reasonable?

Edit: this could work for alists and insertion-ordered tables since it's unobvious how testible!0 & testible.0 should behave, numbers can and should be able to be keys so one can imagine a situation where behavior would be like so:

  arc> (= oble {1 "dream" 2 "bigger" 0 "awake"})
    {1 "dream" 2 "bigger" 0 "awake"}
  arc> oble.0
    "awake"
  arc> oble!0
    "awake"
  arc> oble,0
    "dream"