docs: private static boolean extractSimpleExtents(Variable var, Extents e, boolean row, int length) {
          int lower;
          int upper;
          if( var.getType() == VariableType.INTEGER_SEQUENCE ) {
              IntegerSequence sequence = ((VariableIntegerSequence)var).sequence;
              if( sequence.getType() == IntegerSequence.Type.FOR ) {
                  IntegerSequence.For seqFor = (IntegerSequence.For)sequence;
                  seqFor.initialize(length);
                  if( seqFor.getStep() == 1 ) {
                      lower = seqFor.getStart();
                      upper = seqFor.getEnd();
                  } else {
                      return false;
                  }
              } else {
                  return false;
              }
          } else if( var.getType() == VariableType.SCALAR ) {
              lower = upper = ((VariableInteger)var).value;
          } else {
              throw new RuntimeException("How did a bad variable get put here?!?!");
          }
          if( row ) {
              e.row0 = lower;
              e.row1 = upper;
          } else {
              e.col0 = lower;
              e.col1 = upper;
          }
          return true;
      }