Hey guys In 22.3 Domain-Specific Languages: Configurations, the book introduces the following data example and data definitions for FSM configurations
(define <http://docs.racket-lang.org/htdp-langs/intermediate-lam.html#%28form._%28%28lib._lang%2Fhtdp-intermediate-lambda..rkt%29._define%29%29> xm0 '(machine ((initial "red")) (action ((state "red") (next "green"))) (action ((state "green") (next "yellow"))) (action ((state "yellow") (next "red"))))) ; An XMachine is a nested list of this shape: ; `(machine ((initial ,FSM-State <https://www.htdp.org/2019-02-24/part_two.html#%28tech._fsm._state%29>)) [ List-of <https://www.htdp.org/2019-02-24/part_three.html#%28tech._sim-dd._list._of%29> X1T <https://www.htdp.org/2019-02-24/part_four.html#%28tech._x1t%29>]) ; An X1T is a nested list of this shape: ; `(action ((state ,FSM-State <https://www.htdp.org/2019-02-24/part_two.html#%28tech._fsm._state%29>) ( next ,FSM-State <https://www.htdp.org/2019-02-24/part_two.html#%28tech._fsm._state%29>))) I do no understand the XMachine data definition properly. In the definition it appears that it would be a list with 3 elements: 1*. *'machine 2. `((initial ,FSM-State <https://www.htdp.org/2019-02-24/part_two.html#%28tech._fsm._state%29>)) 3. [List-of <https://www.htdp.org/2019-02-24/part_three.html#%28tech._sim-dd._list._of%29> X1T <https://www.htdp.org/2019-02-24/part_four.html#%28tech._x1t%29>] However, from the data example (and the fact that it is an Xexpr <https://www.htdp.org/2019-02-24/part_four.html#%28tech._xexpr%29>) I know that the intention is different and that it is a list of the form: 1. 'machine 2. `((initial ,FSM-State <https://www.htdp.org/2019-02-24/part_two.html#%28tech._fsm._state%29>)) 3. X1T <https://www.htdp.org/2019-02-24/part_four.html#%28tech._x1t%29>-1 ... X1T <https://www.htdp.org/2019-02-24/part_four.html#%28tech._x1t%29>-n where is seems that [List-of <https://www.htdp.org/2019-02-24/part_three.html#%28tech._sim-dd._list._of%29> X1T <https://www.htdp.org/2019-02-24/part_four.html#%28tech._x1t%29>]is expanded and included in the list ([List-of <https://www.htdp.org/2019-02-24/part_three.html#%28tech._sim-dd._list._of%29> X1T <https://www.htdp.org/2019-02-24/part_four.html#%28tech._x1t%29>] is consed onto) Can you please explain how the given `(machine ((initial ,FSM-State <https://www.htdp.org/2019-02-24/part_two.html#%28tech._fsm._state%29>)) [ List-of <https://www.htdp.org/2019-02-24/part_three.html#%28tech._sim-dd._list._of%29> X1T <https://www.htdp.org/2019-02-24/part_four.html#%28tech._x1t%29>]) translates to this? -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/racket-users/26d8c34b-8ca8-4525-847f-25ba5b6124fa%40googlegroups.com.
