DSL EXPRESSION:
NR == 3 {@v[1]  = $*}


AST:
* statement block
    * cond block
        * operator "=="
            * context variable "NR"
            * int literal "3"
        * statement block
            * assignment "="
                * array or map index access "[]"
                    * direct oosvar value "v"
                    * int literal "1"
                * full record "$*"

