DSL EXPRESSION:
${new} = $a . $b


AST:
* statement block
    * assignment "="
        * direct field value "new"
        * dot operator "."
            * direct field value "a"
            * direct field value "b"

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