[search] Remove stop words

Signed-off-by: x7z4w <x7z4w@noreply.codeberg.org>

libs/search/house_numbers_matcher.cpp

@@ -76,7 +76,7 @@ char const * g_strings[] = {
 // ./clusterize-tag-values.lisp house-number path-to-taginfo-db.db > numbers.txt
 // tail -n +2 numbers.txt  | head -78 | sed 's/^.*) \(.*\) \[.*$/"\1"/g;s/[ -/]//g;s/$/,/' |
 // sort | uniq
-vector<string> const g_patterns = {"BL", "BLN", "BLNSL", "BN", "BNL", "BNSL", "L", "LL", "LN", "LNL", "LNLN", "LNN",
+array<string_view, 48> constexpr g_patterns = {"BL", "BLN", "BLNSL", "BN", "BNL", "BNSL", "L", "LL", "LN", "LNL", "LNLN", "LNN",
                                    "N", "NBL", "NBLN", "NBN", "NBNBN", "NBNL", "NL", "NLBN", "NLL", "NLLN", "NLN",
                                    "NLNL", "NLS", "NLSN", "NN", "NNBN", "NNL", "NNLN", "NNN", "NNS", "NS", "NSN", "NSS",
                                    "S", "SL", "SLL", "SLN", "SN", "SNBNSS", "SNL", "SNN", "SS", "SSN", "SSS", "SSSS",
@@ -85,13 +85,14 @@ vector<string> const g_patterns = {"BL", "BLN", "BLNSL", "BN", "BNL", "BNSL", "L
                                    "NNBNL"};
 
 // List of patterns which look like house numbers more than other patterns. Constructed by hand.
-vector<string> const g_patternsStrict = {"N", "NBN", "NBL", "NL"};
+array<string_view, 4> constexpr g_patternsStrict = {"N", "NBN", "NBL", "NL"};
 
 // List of common synonyms for building parts. Constructed by hand.
 char const * g_buildingPartSynonyms[] = {"building", "bldg", "bld",   "bl",  "unit",     "block", "blk",  "корпус",
                                          "корп",     "кор",  "литер", "лит", "строение", "стр",   "блок", "бл"};
 
 // List of common stop words for buildings. Constructed by hand.
+// TODO: add more stop words?
 UniString const g_stopWords[] = {MakeUniString("дом"), MakeUniString("house"), MakeUniString("д")};
 
 bool IsStopWord(UniString const & s, bool isPrefix)
@@ -167,7 +168,8 @@ class HouseNumberClassifier
 public:
   using Patterns = StringSet<Token::Type, 4>;
 
-  HouseNumberClassifier(vector<string> const & patterns = g_patterns)
+  template <size_t size>
+  HouseNumberClassifier(array<string_view, size> const & patterns)
   {
     for (auto const & p : patterns)
       m_patterns.Add(make_transform_iterator(p.begin(), &CharToType), make_transform_iterator(p.end(), &CharToType));
@@ -590,7 +592,7 @@ bool HouseNumbersMatchRange(std::string_view const & hnRange, TokensT const & qu
 
 bool LooksLikeHouseNumber(UniString const & s, bool isPrefix)
 {
-  static HouseNumberClassifier const classifier;
+  static HouseNumberClassifier const classifier(g_patterns);
   return classifier.LooksGood(s, isPrefix);
 }
 

libs/search/locality_scorer.cpp

@@ -298,7 +298,6 @@ void LocalityScorer::GetDocVecs(uint32_t localityId, vector<DocVec> & dvs) const
     DocVec::Builder builder;
     ForEachNormalizedToken(name, [&](strings::UniString const & token)
     {
-      if (!IsStopWord(token))
       builder.Add(token);
     });
     dvs.emplace_back(std::move(builder));

libs/search/processor.cpp

@@ -69,21 +69,6 @@ m2::RectD GetRectAroundPosition(m2::PointD const & position)
   return mercator::RectByCenterXYAndSizeInMeters(position, kMaxPositionRadiusM);
 }
 
-// Removes all full-token stop words from |tokens|.
-// Does nothing if all tokens are non-prefix stop words.
-void RemoveStopWordsIfNeeded(QueryTokens & tokens, strings::UniString & prefix)
-{
-  size_t numStopWords = 0;
-  for (auto const & token : tokens)
-    if (IsStopWord(token))
-      ++numStopWords;
-
-  if (numStopWords == tokens.size() && prefix.empty())
-    return;
-
-  tokens.erase_if(&IsStopWord);
-}
-
 void TrimLeadingSpaces(string & s)
 {
   while (!s.empty() && strings::IsASCIISpace(s.front()))
@@ -277,9 +262,6 @@ void Processor::SetQuery(string const & query, bool categorialRequest /* = false
     }
   }
 
-  // Remove stopwords *after* FillCategories call (it makes exact tokens match).
-  RemoveStopWordsIfNeeded(m_query.m_tokens, m_query.m_prefix);
-
   if (!m_isCategorialRequest)
   {
     // Assign tokens and prefix to scorer.

libs/search/query_params.cpp

@@ -1482,13 +1482,7 @@ unordered_map<string, vector<string>> const kSynonyms = {
 // QueryParams::Token ------------------------------------------------------------------------------
 void QueryParams::Token::AddSynonym(string const & s)
 {
-  AddSynonym(strings::MakeUniString(s));
+  m_synonyms.push_back(strings::MakeUniString(s));
-}
-
-void QueryParams::Token::AddSynonym(String const & s)
-{
-  if (!IsStopWord(s))
-    m_synonyms.push_back(s);
 }
 
 string DebugPrint(QueryParams::Token const & token)
@@ -1510,10 +1504,11 @@ void QueryParams::ClearStreetIndices()
     AdditionalCommonTokens()
     {
       char const * arr[] = {
-          "the",                       // English
+          "a",  "and", "s",   "the",                       // English
-          "der", "zum", "und", "auf",  // German
+          "am", "an",  "auf", "der", "im",  "und", "zum",  // German
-          "del", "les",                // Spanish
+          "as", "d",   "da",  "de",  "del", "di",  "do",  "du", "e", "el",
-          "в",   "на"                  // Cyrillic
+          "et", "la",  "las", "le",  "les", "los", "o",   "os", "y",  // French, Spanish, Italian
+          "в",  "и",   "на",  "я"                                     // Cyrillic
       };
       for (char const * s : arr)
         m_strings.insert(NormalizeAndSimplifyString(s));

libs/search/query_params.hpp

@@ -28,7 +28,6 @@ public:
     Token(String const & original) : m_original(original) {}
 
     void AddSynonym(std::string const & s);
-    void AddSynonym(String const & s);
 
     template <typename Fn>
     void ForEachSynonym(Fn && fn) const

libs/search/ranking_utils.cpp

@@ -94,42 +94,9 @@ ErrorsMade GetPrefixErrorsMade(QueryParams::Token const & token, strings::UniStr
 }
 }  // namespace impl
 
-bool IsStopWord(UniString const & s)
-{
-  /// @todo Get all common used stop words and take out this array into search_string_utils.cpp module for example.
-  /// Should skip this tokens when building search index?
-  class StopWordsChecker
-  {
-    set<UniString> m_set;
-
-  public:
-    StopWordsChecker()
-    {
-      // Don't want to put _full_ stopwords list, not to break current ranking.
-      // Only 2-letters and the most common.
-      char const * arr[] = {
-          "a",  "s",  "the",                          // English
-          "am", "im", "an",                           // German
-          "d",  "da", "de",  "di", "du", "la", "le",  // French, Spanish, Italian
-          "и",  "я"                                   // Cyrillic
-      };
-      for (char const * s : arr)
-        m_set.insert(MakeUniString(s));
-    }
-    bool Has(UniString const & s) const { return m_set.count(s) > 0; }
-  };
-
-  static StopWordsChecker const swChecker;
-  return swChecker.Has(s);
-}
-
 TokensVector::TokensVector(string_view name)
 {
-  ForEachNormalizedToken(name, [this](strings::UniString && token)
+  m_tokens = NormalizeAndTokenizeString(std::move(name));
-  {
-    if (!IsStopWord(token))
-      m_tokens.push_back(std::move(token));
-  });
 
   Init();
 }

libs/search/ranking_utils.hpp

@@ -180,9 +180,6 @@ struct NameScores
 std::string DebugPrint(NameScore const & score);
 std::string DebugPrint(NameScores const & scores);
 
-// Returns true when |s| is a stop-word and may be removed from a query.
-bool IsStopWord(strings::UniString const & s);
-
 class TokensVector
 {
   std::vector<strings::UniString> m_tokens;

libs/search/search_tests/locality_scorer_test.cpp

@@ -44,11 +44,7 @@ public:
     m_scorer.SetPivotForTesting(pivot);
 
     vector<UniString> tokens;
-    search::ForEachNormalizedToken(query, [&tokens](strings::UniString && token)
+    tokens = NormalizeAndTokenizeString(query);
-    {
-      if (!IsStopWord(token))
-        tokens.push_back(std::move(token));
-    });
 
     m_params.Init(query, tokens, lastTokenIsPrefix);
   }