@Override
public Integer eval(Evaluator evaluator, RuntimeEnvironment localEnv) throws EvaluatorException {
Integer value;
RuntimeEnvironment globalEnv = evaluator.getGlobalEnv();
SymbolTable symbolTable = evaluator.getSymbolTable();
if (localEnv.isBound(nameIndex)) {
value = localEnv.fetch(nameIndex);
} else if (globalEnv.isBound(nameIndex)) {
value = globalEnv.fetch(nameIndex);
} else {
throw new EvaluatorException("Undefined variable: " + symbolTable.getName(nameIndex));
}
return value;
}
