question: private Object doIndex ( Object obj , boolean toLHS , CallStack callstack , Interpreter interpreter ) throws EvalError , ReflectError { int index = getIndexAux ( obj , callstack , interpreter , this ) ; if ( toLHS ) return new LHS ( obj , index ) ; else try { return Reflect . getIndex ( obj , index ) ; } catch ( UtilEvalError e ) { throw e . toEvalError ( this , callstack ) ; } }
target:  array index. Must handle toLHS case.