DSL EXPRESSION:
$new = $["a"]


AST:
* statement block
    * assignment "="
        * direct field value "new"
        * indirect field value "$[]"
            * string literal "a"

a   b   i x          y          new
pan pan 1 0.34679014 0.72680286 pan
eks pan 2 0.75867996 0.52215111 eks
wye wye 3 0.20460331 0.33831853 wye
eks wye 4 0.38139939 0.13418874 eks
