copy method
Implementation
Element copy() {
var copy = Element(type, currentPointer,
inExpressionEvaluation: inExpressionEvaluation);
copy.temporaryVariables = Map.of(temporaryVariables);
copy.evaluationStackHeightWhenPushed = evaluationStackHeightWhenPushed;
copy.functionStartInOuputStream = functionStartInOuputStream;
return copy;
}