A comparison of the two approaches goes in favor of the joint setup: Without the reranker, models generating trees produce less semantic errors and gain higher BLEU/NIST scores.
while some generators keep this division and use a two-step pipeline (walker et al., 2001;Rieser et al., 2010;Dethlefs et al., 2013), others apply a joint model for both tasks (wong and Mooney, 2007;Konstas and Lapata, 2013).