OverlayingRow result = new OverlayingRow(original);
int nfields = rowType.nFields();
for (int i = 0; i < nfields; i++) {
TPreparedExpression expression = pExpressions.get(i);
if (expression != null) {
TEvaluatableExpression evaluation = expression.build();
evaluation.with(original);
evaluation.with(context);
evaluation.with(bindings);
evaluation.evaluate();
result.overlay(i, evaluation.resultValue());