Successfully find arbitrarily large compound expressions.

Previously the program could only safely find two-word compounds. Now it always
finds all of them, even if they are large sentences with many words.

To choose the source for compounds, a notion of dictionary features was added.
It may be utilized later for some more interesting things.

article_maker.cc

@@ -573,12 +573,10 @@ void ArticleRequest::compoundSearchNextStep( bool lastSearchSucceeded )
 
     string footer;
 
-    if ( currentSplittedWordEnd - currentSplittedWordStart > 1 ) // We have something to append
+    if ( lastGoodCompoundResult.size() ) // We have something to append
     {
 //      printf( "Appending\n" );
 
-      --currentSplittedWordEnd;
-
       if ( !firstCompoundWasFound )
       {
         // Append the beginning
@@ -594,7 +592,9 @@ void ArticleRequest::compoundSearchNextStep( bool lastSearchSucceeded )
         footer += " / ";
       }
 
-      footer += linkWord( makeSplittedWordCompound() );
+      footer += linkWord( lastGoodCompoundResult );
+
+      lastGoodCompoundResult.clear();
     }
 
     // Then, start a new search for the next word, if possible
@@ -672,7 +672,8 @@ void ArticleRequest::compoundSearchNextStep( bool lastSearchSucceeded )
 
 //  printf( "Looking up %s\n", qPrintable( currentSplittedWordCompound ) );
 
-  stemmedWordFinder->stemmedMatch( currentSplittedWordCompound, activeDicts, 0, 0, 1 );
+  stemmedWordFinder->prefixMatch( currentSplittedWordCompound, activeDicts, 40, // Would one be enough? Leave 40 to be safe.
+                                  Dictionary::SuitableForCompoundSearching );
 }
 
 QString ArticleRequest::makeSplittedWordCompound()
@@ -707,10 +708,32 @@ void ArticleRequest::individualWordFinished()
     // Check if the aliases are acceptable
     wstring source = Folding::applySimpleCaseOnly( gd::toWString( currentSplittedWordCompound ) );
 
+    bool hadSomething = false;
+
     for( unsigned x = 0; x < results.size(); ++x )
-      if ( source == Folding::applySimpleCaseOnly( gd::toWString( results[ x ].first ) ) )
     {
-        // Ok, good enough
+      if ( results[ x ].second )
+        continue; // We're not interested in suggestions
+
+      wstring result( Folding::applySimpleCaseOnly( gd::toWString( results[ x ].first ) ) );
+
+      if ( source.size() <= result.size() && result.compare( 0, source.size(), source ) == 0 )
+      {
+        // The resulting string begins with the source one
+
+        hadSomething = true;
+
+        if ( source.size() == result.size() )
+        {
+          // Got the match. No need to continue.
+          lastGoodCompoundResult = currentSplittedWordCompound;
+          break;
+        }
+      }
+    }
+
+    if ( hadSomething )
+    {
       compoundSearchNextStep( true );
       return;
     }

article_maker.hh

@@ -100,6 +100,7 @@ class ArticleRequest: public Dictionary::DataRequest
   int currentSplittedWordStart;
   int currentSplittedWordEnd;
   QString currentSplittedWordCompound;
+  QString lastGoodCompoundResult;
   bool firstCompoundWasFound;
 
 public:

btreeidx.hh

@@ -139,6 +139,10 @@ public:
 
   BtreeDictionary( string const & id, vector< string > const & dictionaryFiles );
 
+  /// Btree-indexed dictionaries are usually a good source for compound searches.
+  virtual Dictionary::Features getFeatures() const throw()
+  { return Dictionary::SuitableForCompoundSearching; }
+
   /// This function does the search using the btree index. Derivatives
   /// need not to implement this function.
   virtual sptr< Dictionary::WordSearchRequest > prefixMatch( wstring const &,

dictionary.hh

@@ -222,6 +222,18 @@ public:
   { return data; }
 };
 
+/// Dictionary features. Different dictionaries can possess different features,
+/// which hint at some of their aspects.
+enum Feature
+{
+  /// No features
+  NoFeatures = 0,
+  /// The dictionary is suitable to query when searching for compound expressions.
+  SuitableForCompoundSearching = 1
+};
+
+Q_DECLARE_FLAGS( Features, Feature )
+Q_DECLARE_OPERATORS_FOR_FLAGS( Features )
 
 /// A dictionary. Can be used to query words.
 class Class
@@ -259,6 +271,11 @@ public:
   /// description etc. All strings are in utf8.
   virtual map< Property, string > getProperties() throw()=0;
 
+  /// Returns the features the dictionary possess. See the Feature enum for
+  /// their list.
+  virtual Features getFeatures() const throw()
+  { return NoFeatures; }
+
   /// Returns the number of articles in the dictionary.
   virtual unsigned long getArticleCount() throw()=0;
 

wordfinder.cc

@@ -32,7 +32,9 @@ WordFinder::~WordFinder()
 }
 
 void WordFinder::prefixMatch( QString const & str,
-                              std::vector< sptr< Dictionary::Class > > const & dicts )
+                              std::vector< sptr< Dictionary::Class > > const & dicts,
+                              unsigned long maxResults,
+                              Dictionary::Features features )
 {
   cancel();
 
@@ -40,6 +42,8 @@ void WordFinder::prefixMatch( QString const & str,
   searchType = PrefixMatch;
   inputWord = str;
   inputDicts = &dicts;
+  requestedMaxResults = maxResults;
+  requestedFeatures = features;
 
   resultsArray.clear();
   resultsIndex.clear();
@@ -59,7 +63,8 @@ void WordFinder::stemmedMatch( QString const & str,
                                std::vector< sptr< Dictionary::Class > > const & dicts,
                                unsigned minLength,
                                unsigned maxSuffixVariation,
-                               unsigned long maxResults )
+                               unsigned long maxResults,
+                               Dictionary::Features features )
 {
   cancel();
 
@@ -67,9 +72,10 @@ void WordFinder::stemmedMatch( QString const & str,
   searchType = StemmedMatch;
   inputWord = str;
   inputDicts = &dicts;
+  requestedMaxResults = maxResults;
+  requestedFeatures = features;
   stemmedMinLength = minLength;
   stemmedMaxSuffixVariation = maxSuffixVariation;
-  stemmedMaxResults = maxResults;
 
   resultsArray.clear();
   resultsIndex.clear();
@@ -111,12 +117,15 @@ void WordFinder::startSearch()
 
   for( size_t x = 0; x < inputDicts->size(); ++x )
   {
+    if ( ( (*inputDicts)[ x ]->getFeatures() & requestedFeatures ) != requestedFeatures )
+      continue;
+
     for( size_t y = 0; y < allWordWritings.size(); ++y )
     {
       sptr< Dictionary::WordSearchRequest > sr =
         ( searchType == PrefixMatch ) ?
-          (*inputDicts)[ x ]->prefixMatch( allWordWritings[ y ], 40 ) :
+          (*inputDicts)[ x ]->prefixMatch( allWordWritings[ y ], requestedMaxResults ) :
-          (*inputDicts)[ x ]->stemmedMatch( allWordWritings[ y ], stemmedMinLength, stemmedMaxSuffixVariation, stemmedMaxResults );
+          (*inputDicts)[ x ]->stemmedMatch( allWordWritings[ y ], stemmedMinLength, stemmedMaxSuffixVariation, requestedMaxResults );
   
       connect( sr.get(), SIGNAL( finished() ),
                this, SLOT( requestFinished() ), Qt::QueuedConnection );

wordfinder.hh

@@ -42,9 +42,10 @@ private:
     PrefixMatch,
     StemmedMatch
   } searchType;
+  unsigned long requestedMaxResults;
+  Dictionary::Features requestedFeatures;
   unsigned stemmedMinLength;
   unsigned stemmedMaxSuffixVariation;
-  unsigned long stemmedMaxResults;
 
   std::vector< sptr< Dictionary::Class > > const * inputDicts;
 
@@ -74,10 +75,14 @@ public:
   /// the exact matches would be found. All search results are put into a single
   /// list containing the exact matches first, then the prefix ones. Duplicate
   /// matches from different dictionaries are merged together.
+  /// If a list of features is specified, the search will only be performed in
+  /// the dictionaries which possess all the features requested.
   /// If there already was a prefixMatch operation underway, it gets cancelled
   /// and the new one replaces it.
   void prefixMatch( QString const &,
-                    std::vector< sptr< Dictionary::Class > > const & );
+                    std::vector< sptr< Dictionary::Class > > const &,
+                    unsigned long maxResults = 40,
+                    Dictionary::Features = Dictionary::NoFeatures );
 
   /// Do a stemmed-match search in the given list of dictionaries. All comments
   /// from prefixMatch() generally apply as well.
@@ -85,7 +90,8 @@ public:
                      std::vector< sptr< Dictionary::Class > > const &,
                      unsigned minLength = 3,
                      unsigned maxSuffixVariation = 3,
-                     unsigned long maxResults = 30 );
+                     unsigned long maxResults = 30,
+                     Dictionary::Features = Dictionary::NoFeatures );
   
   /// Returns the vector containing search results from the last operation.
   /// If it didn't finish yet, the result is not final and may be changing