pipe = new ReadableDocument(runtime);
} else if (binding.getBindingType() == Binding.DOCUMENT_BINDING) {
DocumentBinding dbinding = (DocumentBinding) binding;
pipe = runtime.getConfigurer().getXMLCalabashConfigurer().makeReadableDocument(runtime, dbinding);
} else if (binding.getBindingType() == Binding.DATA_BINDING) {
DataBinding dbinding = (DataBinding) binding;
pipe = runtime.getConfigurer().getXMLCalabashConfigurer().makeReadableData(runtime, dbinding);
} else if (binding.getBindingType() == Binding.ERROR_BINDING) {
XCompoundStep step = parent;
while (! (step instanceof XCatch)) {
step = step.getParent();