Insert word completion: Use subsequence matching if prefix failed

3 files changed, 25 insertions, 12 deletions

diff --git a/src/insert_completer.cc b/src/insert_completer.cc
index 1f17e888..205b99e8 100644
--- a/src/insert_completer.cc
+++ b/src/insert_completer.cc
@@ -28,7 +28,7 @@ WordDB& get_word_db(const Buffer& buffer)
     return cache_val.as<WordDB>();
 }
 
-template<bool other_buffers>
+template<bool other_buffers, bool subseq>
 InsertCompletion complete_word(const Buffer& buffer, ByteCoord cursor_pos)
 {
    auto pos = buffer.iterator_at(cursor_pos);
@@ -51,7 +51,8 @@ InsertCompletion complete_word(const Buffer& buffer, ByteCoord cursor_pos)
 
     auto& word_db = get_word_db(buffer);
     std::unordered_set<String> matches;
-    auto bufmatches = word_db.find_prefix(prefix);
+    auto bufmatches = subseq ? word_db.find_subsequence(prefix)
+                             : word_db.find_prefix(prefix);
     matches.insert(bufmatches.begin(), bufmatches.end());
 
     if (word_db.get_word_occurences(current_word) <= 1)
@@ -63,7 +64,9 @@ InsertCompletion complete_word(const Buffer& buffer, ByteCoord cursor_pos)
         {
             if (buf.get() == &buffer)
                 continue;
-            bufmatches = get_word_db(*buf).find_prefix(prefix);
+            auto buf_word_db = get_word_db(*buf);
+            bufmatches = subseq ? buf_word_db.find_subsequence(prefix)
+                                : buf_word_db.find_prefix(prefix);
             matches.insert(bufmatches.begin(), bufmatches.end());
         }
     }
@@ -285,14 +288,12 @@ bool InsertCompleter::setup_ifn()
                 }))
                 return true;
             if (completer == "word=buffer" and
-                try_complete([this](const Buffer& buffer, ByteCoord cursor_pos) {
-                    return complete_word<false>(buffer, cursor_pos);
-                }))
+                (try_complete(complete_word<false, false>) or
+                 try_complete(complete_word<false, true>)))
                 return true;
             if (completer == "word=all" and
-                try_complete([this](const Buffer& buffer, ByteCoord cursor_pos) {
-                    return complete_word<true>(buffer, cursor_pos);
-                }))
+                (try_complete(complete_word<true, false>) or
+                 try_complete(complete_word<true, true>)))
                 return true;
         }
         return false;
@@ -370,9 +371,7 @@ void InsertCompleter::explicit_file_complete()
 
 void InsertCompleter::explicit_word_complete()
 {
-    try_complete([this](const Buffer& buffer, ByteCoord cursor_pos) {
-        return complete_word<true>(buffer, cursor_pos);
-    });
+    try_complete(complete_word<true, true>);
 }
 
 void InsertCompleter::explicit_line_complete()
diff --git a/src/word_db.cc b/src/word_db.cc
index dc08f102..e3be4245 100644
--- a/src/word_db.cc
+++ b/src/word_db.cc
@@ -118,6 +118,19 @@ std::vector<String> WordDB::find_prefix(const String& prefix)
     return res;
 }
 
+std::vector<String> WordDB::find_subsequence(const String& subsequence)
+{
+    update_db();
+
+    std::vector<String> res;
+    for (auto it = m_words.begin(); it != m_words.end(); ++it)
+    {
+        if (subsequence_match(it->first, subsequence))
+            res.push_back(it->first);
+    }
+    return res;
+}
+
 int WordDB::get_word_occurences(const String& word) const
 {
     auto it = m_words.find(word);
diff --git a/src/word_db.hh b/src/word_db.hh
index 2349a618..043f9960 100644
--- a/src/word_db.hh
+++ b/src/word_db.hh
@@ -17,6 +17,7 @@ public:
     WordDB(const Buffer& buffer);
 
     std::vector<String> find_prefix(const String& prefix);
+    std::vector<String> find_subsequence(const String& subsequence);
     int get_word_occurences(const String& word) const;
 
     using WordList = std::map<String, int>;