NetLogo 7.0.0-beta2:

sr:set-agent

sr:set-agent r-variable-name agent or agentset agent-variable-name sr:set-agent r-variable-name agent or agentset agent-variable-name1 agent-variable-name2...

Creates a new named list in R with the given variable name. If you want multiple agent variables make sure to surround the command in parenthesis.

clear-all
sr:setup
create-turtles 2
ask turtle 0 [ set color red set xcor 5]
ask turtle 1 [ set color blue set xcor -5]
(sr:set-agent "t0" turtle 0 "who" "color" "xcor" "hidden?")
sr:run "print(typeof(t0))"
;; [1] "list"
sr:run "print(t0)"
;; $who
;; [1] 0
;;
;; $color
;; [1] 15
;;
;; $xcor
;; [1] 5
;;
;; $`hidden?`
;; [1] FALSE

Take me to the full Simple R Extension Dictionary