cleanup some fixmes

git-svn-id: https://svn.code.sf.net/p/jackcess/code/jackcess/branches/exprs@1158 f203690c-595d-4dc9-a70b-905162fa7fd2

src/main/java/com/healthmarketscience/jackcess/impl/expr/Expressionator.java

@@ -422,8 +422,7 @@ public class Expressionator
         ExpressionTokenizer.tokenize(exprType, exprStr, context));
 
     if(tokens == null) {
-      // FIXME, NULL_EXPR?
-      return null;
+      throw new ParseException("null/empty expression");
     }
 
     TokBuf buf = new TokBuf(exprType, tokens, context);
@@ -2063,8 +2062,6 @@ public class Expressionator
         throw new EvalException("Condition evaluated to Null");
       }
 
-      // FIXME, access seems to type coerce all "fields" (including <this>), but not constants
-
       return val.getAsBoolean();
     }
   }