getUsedVariables method

@override Set<String> getUsedVariables()

Get mentioned variables that are required to evaluate the expression

Searches the math tree for any MathVariable instances and returns a set of their names.

Implementation

@override
Set<String> getUsedVariables() {
  return {
    for (var l in arguments.map<Set<String>>((e) => e.getUsedVariables()))
      ...l
  };
}