From 2edf6020d71b4f728a473780a8f109bbb98efe2c Mon Sep 17 00:00:00 2001
From: Chris Dyer <redpony@gmail.com>
Date: Sat, 24 May 2014 02:09:49 -0400
Subject: support per sentence tree-to-string grammars

---
 decoder/tree2string_translator.cc | 46 +++++++++++++++++++++++++++++++++------
 1 file changed, 39 insertions(+), 7 deletions(-)

diff --git a/decoder/tree2string_translator.cc b/decoder/tree2string_translator.cc
index 7b37887e..b5b47d5d 100644
--- a/decoder/tree2string_translator.cc
+++ b/decoder/tree2string_translator.cc
@@ -5,6 +5,7 @@
 #include <unordered_set>
 #include <boost/shared_ptr.hpp>
 #include <boost/functional/hash.hpp>
+#include "fast_lexical_cast.hpp"
 #include "tree_fragment.h"
 #include "translator.h"
 #include "hg.h"
@@ -23,7 +24,7 @@ struct Tree2StringGrammarNode {
 
 // this needs to be rewritten so it is fast and checks errors well
 // use a lexer probably
-void ReadTree2StringGrammar(istream* in, Tree2StringGrammarNode* root, bool has_multiple_states) {
+static void ReadTree2StringGrammar(istream* in, Tree2StringGrammarNode* root, bool has_multiple_states) {
   string line;
   while(getline(*in, line)) {
     size_t pos = line.find("|||");
@@ -142,10 +143,12 @@ void AddDummyGoalNode(Hypergraph* hg) {
 struct Tree2StringTranslatorImpl {
   vector<boost::shared_ptr<Tree2StringGrammarNode>> root;
   bool add_pass_through_rules;
+  bool has_multiple_states;
   unsigned remove_grammars;
   Tree2StringTranslatorImpl(const boost::program_options::variables_map& conf,
                             bool has_multiple_states) :
-      add_pass_through_rules(conf.count("add_pass_through_rules")) {
+      add_pass_through_rules(conf.count("add_pass_through_rules")),
+      has_multiple_states(has_multiple_states) {
     if (conf.count("grammar")) {
       const vector<string> gf = conf["grammar"].as<vector<string>>();
       root.resize(gf.size());
@@ -158,6 +161,15 @@ struct Tree2StringTranslatorImpl {
     }
   }
 
+  // loads a per-sentence grammar
+  void LoadSupplementalGrammar(const string& gfile) {
+    root.resize(root.size() + 1);
+    root.back().reset(new Tree2StringGrammarNode);
+    ++remove_grammars;
+    ReadFile rf(gfile);
+    ReadTree2StringGrammar(rf.stream(), root.back().get(), has_multiple_states);
+  }
+
   void CreatePassThroughRules(const cdec::TreeFragment& tree) {
     static const int kFIDlex = FD::Convert("PassThrough_Lexical");
     static const int kFIDabs = FD::Convert("PassThrough_Abstract");
@@ -227,7 +239,7 @@ struct Tree2StringTranslatorImpl {
   }
 
   void RemoveGrammars() {
-    assert(remove_grammars < root.size());
+    assert(remove_grammars <= root.size());
     root.resize(root.size() - remove_grammars);
   }
 
@@ -235,7 +247,6 @@ struct Tree2StringTranslatorImpl {
                  SentenceMetadata* smeta,
                  const vector<double>& weights,
                  Hypergraph* minus_lm_forest) {
-    remove_grammars = 0;
     cdec::TreeFragment input_tree(input, false);
     if (add_pass_through_rules) CreatePassThroughRules(input_tree);
     Hypergraph hg;
@@ -371,6 +382,30 @@ Tree2StringTranslator::Tree2StringTranslator(const boost::program_options::varia
                                              bool has_multiple_states) :
   pimpl_(new Tree2StringTranslatorImpl(conf, has_multiple_states)) {}
 
+void Tree2StringTranslator::ProcessMarkupHintsImpl(const map<string, string>& kv) {
+  pimpl_->remove_grammars = 0;
+  if (kv.find("grammar0") != kv.end()) {
+    cerr << "SGML tag grammar0 is not expected (order is: grammar, grammar1, grammar2, ...)\n";
+    abort();
+  }
+  unsigned gc = 0;
+  set<string> loaded;
+  while(true) {
+    string gkey = "grammar";
+    if (gc > 0) gkey += boost::lexical_cast<string>(gc);
+    ++gc;
+    map<string,string>::const_iterator it = kv.find(gkey);
+    if (it == kv.end()) break;
+    const string& gfile = it->second;
+    if (loaded.count(gfile) == 1) {
+      cerr << "Attempting to load " << gfile << " twice!\n";
+      abort();
+    }
+    loaded.insert(gfile);
+    pimpl_->LoadSupplementalGrammar(gfile);
+  }
+}
+
 bool Tree2StringTranslator::TranslateImpl(const string& input,
                                SentenceMetadata* smeta,
                                const vector<double>& weights,
@@ -378,9 +413,6 @@ bool Tree2StringTranslator::TranslateImpl(const string& input,
   return pimpl_->Translate(input, smeta, weights, minus_lm_forest);
 }
 
-void Tree2StringTranslator::ProcessMarkupHintsImpl(const map<string, string>& kv) {
-}
-
 void Tree2StringTranslator::SentenceCompleteImpl() {
   pimpl_->RemoveGrammars();
 }
-- 
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