.col);
</PRE>

<P>To get other forms of error messages a programmer might derive another
subclass from <I>ErrorStream</I> , and override <I>SemErr</I> so that the
error code is transformed into an error message in some other way.

The suggested approach is to include code like:

<PRE>   class MyErrorStream extends ErrorStream {

     void SemErr(int n, int line, int col) {
       String s;
       count++;
       switch (n) {
         case 0:  s = "invalid character"; break;
         case 1:  s = "My Message