feat(translator): look at preceding text when making sentence

src/rime/commit_history.h

@@ -29,6 +29,9 @@ class CommitHistory : public list<CommitRecord> {
   void Push(const KeyEvent& key_event);
   void Push(const Composition& composition, const string& input);
   string repr() const;
+  string latest_text() const {
+    return empty() ? string() : back().text;
+  }
 };
 
 }  // Namespace rime

src/rime/gear/poet.cc

@@ -42,7 +42,8 @@ bool Poet::LeftAssociateCompare(const Sentence& one, const Sentence& other) {
 }
 
 an<Sentence> Poet::MakeSentence(const WordGraph& graph,
-                                size_t total_length) {
+                                size_t total_length,
+                                const string& preceding_text) {
   // TODO: save more intermediate sentence candidates
   map<int, an<Sentence>> sentences;
   sentences[0] = New<Sentence>(language_);
@@ -61,7 +62,8 @@ an<Sentence> Poet::MakeSentence(const WordGraph& graph,
       const DictEntryList& entries(x.second);
       for (const auto& entry : entries) {
         auto new_sentence = New<Sentence>(*sentences[start_pos]);
-        new_sentence->Extend(*entry, end_pos, is_rear, grammar_.get());
+        new_sentence->Extend(
+            *entry, end_pos, is_rear, preceding_text, grammar_.get());
         if (sentences.find(end_pos) == sentences.end() ||
             compare_(*sentences[end_pos], *new_sentence)) {
           DLOG(INFO) << "updated sentences " << end_pos << ") with "

src/rime/gear/poet.h

@@ -35,7 +35,9 @@ class Poet {
        Compare compare = CompareWeight);
   ~Poet();
 
-  an<Sentence> MakeSentence(const WordGraph& graph, size_t total_length);
+  an<Sentence> MakeSentence(const WordGraph& graph,
+                            size_t total_length,
+                            const string& preceding_text);
 
  private:
   const Language* language_;

src/rime/gear/script_translator.cc

@@ -214,6 +214,11 @@ string ScriptTranslator::Spell(const Code& code) {
   return result;
 }
 
+string ScriptTranslator::GetPrecedingText() const {
+  return contextual_suggestions_ ?
+      engine_->context()->commit_history().latest_text() : string();
+}
+
 bool ScriptTranslator::Memorize(const CommitEntry& commit_entry) {
   bool update_elements = false;
   // avoid updating single character entries within a phrase which is
@@ -538,12 +543,14 @@ an<Sentence> ScriptTranslation::MakeSentence(Dictionary* dict,
       }
     }
   }
-  auto sentence = poet_->MakeSentence(graph, syllable_graph.interpreted_length);
-  if (sentence) {
+  if (auto sentence = poet_->MakeSentence(graph,
+                                          syllable_graph.interpreted_length,
+                                          translator_->GetPrecedingText())) {
     sentence->Offset(start_);
     sentence->set_syllabifier(syllabifier_);
+    return sentence;
   }
-  return sentence;
+  return nullptr;
 }
 
 }  // namespace rime

src/rime/gear/script_translator.h

@@ -37,6 +37,7 @@ class ScriptTranslator : public Translator,
 
   string FormatPreedit(const string& preedit);
   string Spell(const Code& code);
+  string GetPrecedingText() const;
 
   // options
   int max_homophones() const { return max_homophones_; }

src/rime/gear/table_translator.cc

@@ -342,7 +342,9 @@ bool TableTranslator::Memorize(const CommitEntry& commit_entry) {
         }
         string phrase;
         for (; it != history.rend(); ++it) {
-          if (it->type != "table" && it->type != "sentence" && it->type != "uniquified")
+          if (it->type != "table" &&
+              it->type != "sentence" &&
+              it->type != "uniquified")
             break;
           if (phrase.empty()) {
             phrase = it->text;  // last word
@@ -362,6 +364,11 @@ bool TableTranslator::Memorize(const CommitEntry& commit_entry) {
   return true;
 }
 
+string TableTranslator::GetPrecedingText() const {
+  return contextual_suggestions_ ?
+      engine_->context()->commit_history().latest_text() : string();
+}
+
 // SentenceSyllabifier
 
 class SentenceSyllabifier : public PhraseSyllabifier {
@@ -680,7 +687,9 @@ TableTranslator::MakeSentence(const string& input, size_t start,
       }
     }
   }
-  if (auto sentence = poet_->MakeSentence(graph, input.length())) {
+  if (auto sentence = poet_->MakeSentence(graph,
+                                          input.length(),
+                                          GetPrecedingText())) {
     auto result = Cached<SentenceTranslation>(
         this,
         std::move(sentence),

src/rime/gear/table_translator.h

@@ -35,7 +35,7 @@ class TableTranslator : public Translator,
   an<Translation> MakeSentence(const string& input,
                                        size_t start,
                                        bool include_prefix_phrases = false);
-
+  string GetPrecedingText() const;
   UnityTableEncoder* encoder() const { return encoder_.get(); }
 
  protected:

src/rime/gear/translator_commons.cc

@@ -91,8 +91,10 @@ bool Spans::HasVertex(size_t vertex) const {
 void Sentence::Extend(const DictEntry& entry,
                       size_t end_pos,
                       bool is_rear,
+                      const string& preceding_text,
                       Grammar* grammar) {
-  entry_->weight += Grammar::Evaluate(text(), entry, is_rear, grammar);
+  const string& context = empty() ? preceding_text : text();
+  entry_->weight += Grammar::Evaluate(context, entry, is_rear, grammar);
   entry_->text.append(entry.text);
   entry_->code.insert(entry_->code.end(),
                       entry.code.begin(),
@@ -118,6 +120,8 @@ TranslatorOptions::TranslatorOptions(const Ticket& ticket) {
     config->GetString(ticket.name_space + "/delimiter", &delimiters_) ||
         config->GetString("speller/delimiter", &delimiters_);
     config->GetString(ticket.name_space + "/tag", &tag_);
+    config->GetBool(ticket.name_space + "/contextual_suggestions",
+                    &contextual_suggestions_);
     config->GetBool(ticket.name_space + "/enable_completion",
                     &enable_completion_);
     config->GetBool(ticket.name_space + "/strict_spelling",

src/rime/gear/translator_commons.h

@@ -124,6 +124,7 @@ class Sentence : public Phrase {
   void Extend(const DictEntry& entry,
               size_t end_pos,
               bool is_rear,
+              const string& preceding_text,
               Grammar* grammar);
   void Offset(size_t offset);
 
@@ -159,6 +160,10 @@ class TranslatorOptions {
   const string& delimiters() const { return delimiters_; }
   const string& tag() const { return tag_; }
   void set_tag(const string& tag) { tag_ = tag; }
+  bool contextual_suggestions() const { return contextual_suggestions_; }
+  void set_contextual_suggestions(bool enabled) {
+    contextual_suggestions_ = enabled;
+  }
   bool enable_completion() const { return enable_completion_; }
   void set_enable_completion(bool enabled) { enable_completion_ = enabled; }
   bool strict_spelling() const { return strict_spelling_; }
@@ -171,6 +176,7 @@ class TranslatorOptions {
  protected:
   string delimiters_;
   string tag_ = "abc";
+  bool contextual_suggestions_ = false;
   bool enable_completion_ = true;
   bool strict_spelling_ = false;
   double initial_quality_ = 0.;