How to get all variables from an expression

[star2478]

Hi
How to get all variables from parsing an expression? For example

• an expression:

let arr = filter(user_list, {.user_id == "xxxx"}); 
len(arr)>0? (arr[0].mobile=="123"?arr[0].employee:(arr[0].mobile=="13800001111"?arr[0].employee2:"0") ) :-1

• all variables: user_list, user_id, mobile, employee, employee2

[antonmedv]

Here is a good example: https://expr-lang.org/docs/visitor