This variable holds the current state of internal testing mechanims of all-in and all-in-parallel, and enables a neuron to fire a symbol relative to the position of the found pattern.
This means that if you are looking for an all-in pattern (a c), and it is found, then you'll be able to fire a symbol which is in the middle of the found pattern.
Example clarifies:
(def-neuron rules
(all-in 1 '(a c) -10 10) (transpose-symbol 'b trpos)
(otherwise '=)
)
(run-neuron 'rules '(a c b d))
--> (b = c =)
Notice how the neuron first finds a c and fires a symbol b in between them. Then it proceeds into the next position and finds nothing. Then it finds b d (same relations as a c), and fires the symbol c which is between these symbols.
trpos with combination of transpose-symbol has lots of use when finding patterns,which fire relative patterns.
