1 files changed, 9 insertions, 3 deletions

diff --git a/decoder/decoder.cc b/decoder/decoder.cc
index ff068be9..2c3a06de 100644
--- a/decoder/decoder.cc
+++ b/decoder/decoder.cc
@@ -416,6 +416,7 @@ DecoderImpl::DecoderImpl(po::variables_map& conf, int argc, char** argv, istream
         ("csplit_output_plf", "(Compound splitter) Output lattice in PLF format")
         ("csplit_preserve_full_word", "(Compound splitter) Always include the unsegmented form in the output lattice")
         ("extract_rules", po::value<string>(), "Extract the rules used in translation (de-duped) to this file")
+        ("show_derivations", po::value<string>(), "Directory to print the derivation structures to")
         ("graphviz","Show (constrained) translation forest in GraphViz format")
         ("max_translation_beam,x", po::value<int>(), "Beam approximation to get max translation from the chart")
         ("max_translation_sample,X", po::value<int>(), "Sample the max translation from the chart")
@@ -426,6 +427,7 @@ DecoderImpl::DecoderImpl(po::variables_map& conf, int argc, char** argv, istream
         ("vector_format",po::value<string>()->default_value("b64"), "Sparse vector serialization format for feature expectations or gradients, includes (text or b64)")
         ("combine_size,C",po::value<int>()->default_value(1), "When option -G is used, process this many sentence pairs before writing the gradient (1=emit after every sentence pair)")
         ("forest_output,O",po::value<string>(),"Directory to write forests to");
+
   // ob.AddOptions(&opts);
 #ifdef FSA_RESCORING
   po::options_description cfgo(cfg_options.description());
@@ -677,6 +679,7 @@ DecoderImpl::DecoderImpl(po::variables_map& conf, int argc, char** argv, istream
   kbest = conf.count("k_best");
   unique_kbest = conf.count("unique_k_best");
   get_oracle_forest = conf.count("get_oracle_forest");
+  oracle.show_derivation=conf.count("show_derivations");
 
 #ifdef FSA_RESCORING
   cfg_options.Validate();
@@ -938,7 +941,8 @@ bool DecoderImpl::Decode(const string& input, DecoderObserver* o) {
   } else {
     if (kbest && !has_ref) {
       //TODO: does this work properly?
-      oracle.DumpKBest(sent_id, forest, conf["k_best"].as<int>(), unique_kbest,"-");
+      const string deriv_fname = conf.count("show_derivations") ? str("show_derivations",conf) : "-";
+      oracle.DumpKBest(sent_id, forest, conf["k_best"].as<int>(), unique_kbest,"-", deriv_fname);
     } else if (csplit_output_plf) {
       cout << HypergraphIO::AsPLF(forest, false) << endl;
     } else {
@@ -1055,8 +1059,10 @@ bool DecoderImpl::Decode(const string& input, DecoderObserver* o) {
         }
       }
       if (conf.count("graphviz")) forest.PrintGraphviz();
-      if (kbest)
-        oracle.DumpKBest(sent_id, forest, conf["k_best"].as<int>(), unique_kbest,"-");
+      if (kbest) {
+        const string deriv_fname = conf.count("show_derivations") ? str("show_derivations",conf) : "-";
+        oracle.DumpKBest(sent_id, forest, conf["k_best"].as<int>(), unique_kbest,"-", deriv_fname);
+      }
       if (conf.count("show_conditional_prob")) {
         const prob_t ref_z = Inside<prob_t, EdgeProb>(forest);
         cout << (log(ref_z) - log(first_z)) << endl << flush;