How to use

isDefined

method

in

jscl.math.function.IConstant

@Nonnull
public static Set<Constant> getNotSystemConstants(@Nonnull Generic expression) {
  final Set<Constant> notSystemConstants = new HashSet<Constant>();
  for (Constant constant : expression.getConstants()) {
    IConstant var = Locator.getInstance().getEngine().getVarsRegistry().get(constant.getName());
    if (var != null && !var.isSystem() && !var.isDefined()) {
      notSystemConstants.add(constant);
    }
  }
  return notSystemConstants;
}

final IConstant var = Locator.getInstance().getEngine().getVarsRegistry().get(varName);
if (var != null) {
  if (!var.isDefined()) {
    undefinedVars.add(var);
    result.append(varName);