Refactor RegexIterator to use a Sentinel

4 files changed, 52 insertions, 83 deletions

diff --git a/src/highlighters.cc b/src/highlighters.cc
index a45b5ee7..1d2624c3 100644
--- a/src/highlighters.cc
+++ b/src/highlighters.cc
@@ -361,20 +361,17 @@ private:
     void add_matches(const Buffer& buffer, MatchList& matches, BufferRange range)
     {
         kak_assert(matches.size() % m_faces.size() == 0);
-        using RegexIt = RegexIterator<BufferIterator>;
-        RegexIt re_it{get_iterator(buffer, range.begin),
-                      get_iterator(buffer, range.end),
-                      buffer.begin(), buffer.end(), m_regex,
-                      match_flags(is_bol(range.begin),
-                                  is_eol(buffer, range.end),
-                                  is_bow(buffer, range.begin),
-                                  is_eow(buffer, range.end))};
-        RegexIt re_end;
-        for (; re_it != re_end; ++re_it)
+        for (auto&& match : RegexIterator{get_iterator(buffer, range.begin),
+                                          get_iterator(buffer, range.end),
+                                          buffer.begin(), buffer.end(), m_regex,
+                                          match_flags(is_bol(range.begin),
+                                                      is_eol(buffer, range.end),
+                                                      is_bow(buffer, range.begin),
+                                                      is_eow(buffer, range.end))})
         {
             for (auto& face : m_faces)
             {
-                const auto& sub = (*re_it)[face.first];
+                const auto& sub = match[face.first];
                 matches.push_back({sub.first.coord(), sub.second.coord()});
             }
         }
@@ -1647,9 +1644,8 @@ using RegexMatchList = Vector<RegexMatch, MemoryDomain::Regions>;
 void append_matches(const Buffer& buffer, LineCount line, RegexMatchList& matches, const Regex& regex, bool capture)
 {
     auto l = buffer[line];
-    for (RegexIterator<const char*> it{l.begin(), l.end(), regex}, end{}; it != end; ++it)
+    for (auto&& m : RegexIterator{l.begin(), l.end(), regex})
     {
-        auto& m = *it;
         const bool with_capture = capture and m[1].matched and
                                   m[0].second - m[0].first < std::numeric_limits<uint16_t>::max();
         matches.push_back({
diff --git a/src/regex.hh b/src/regex.hh
index 4d7cc5f0..4aa916c9 100644
--- a/src/regex.hh
+++ b/src/regex.hh
@@ -168,77 +168,58 @@ template<typename Iterator, MatchDirection direction = MatchDirection::Forward>
 struct RegexIterator
 {
     using ValueType = MatchResults<Iterator>;
+    struct Sentinel{};
+    struct It
+    {
+        It(RegexIterator& base) : m_base(base), m_valid{m_base.next()} {}
+
+        const ValueType& operator*() const { kak_assert(m_valid); return m_base.m_results; }
+        const ValueType* operator->() const { kak_assert(m_valid); return &m_base.m_results; }
+
+        It& operator++() { m_valid = m_base.next(); return *this; }
+
+        RegexIterator& m_base;
+        bool m_valid;
+    };
+
+    friend bool operator==(const It& lhs, Sentinel) { return not lhs.m_valid; }
+    friend bool operator!=(const It& lhs, Sentinel) { return lhs.m_valid; }
 
-    RegexIterator() = default;
     RegexIterator(Iterator begin, Iterator end,
                   Iterator subject_begin, Iterator subject_end,
-                  const Regex& re,
-                  RegexExecFlags flags = RegexExecFlags::None)
-        : m_program{re.impl()}, m_next_pos{direction == MatchDirection::Forward ? begin : end},
+                  const Regex& re, RegexExecFlags flags = RegexExecFlags::None)
+        : m_vm{*re.impl()}, m_next_pos{direction == MatchDirection::Forward ? begin : end},
           m_begin{std::move(begin)}, m_end{std::move(end)},
           m_subject_begin{std::move(subject_begin)}, m_subject_end{std::move(subject_end)},
-          m_flags{flags}
-    {
-        next();
-    }
+          m_flags{flags} {}
 
     RegexIterator(const Iterator& begin, const Iterator& end, const Regex& re,
                   RegexExecFlags flags = RegexExecFlags::None)
         : RegexIterator{begin, end, begin, end, re, flags} {}
 
-    const ValueType& operator*() const { kak_assert(m_program); return m_results; }
-    const ValueType* operator->() const { kak_assert(m_program); return &m_results; }
-
-    RegexIterator& operator++()
-    {
-        next();
-        return *this;
-    }
-
-    friend bool operator==(const RegexIterator& lhs, const RegexIterator& rhs)
-    {
-        if (lhs.m_program == nullptr and rhs.m_program == nullptr)
-            return true;
-
-        return lhs.m_program == rhs.m_program and
-               lhs.m_next_pos == rhs.m_next_pos and
-               lhs.m_end == rhs.m_end and
-               lhs.m_flags == rhs.m_flags and
-               lhs.m_results == rhs.m_results;
-    }
-
-    friend bool operator!=(const RegexIterator& lhs, const RegexIterator& rhs)
-    {
-        return not (lhs == rhs);
-    }
-
-    RegexIterator begin() { return *this; }
-    RegexIterator end() { return {}; }
+    It begin() { return {*this}; }
+    Sentinel end() const { return {}; }
 
 private:
-    void next()
+    bool next()
     {
-        kak_assert(m_program);
-
         auto additional_flags = RegexExecFlags::Search;
         if (m_results.size() and m_results[0].first == m_results[0].second)
             additional_flags |= RegexExecFlags::NotInitialNull;
 
-        ThreadedRegexVM<Iterator, direction> vm{*m_program};
         constexpr bool forward = direction == MatchDirection::Forward;
 
-        if (vm.exec(forward ? m_next_pos : m_begin, forward ? m_end : m_next_pos,
-                    m_subject_begin, m_subject_end, m_flags | additional_flags))
-        {
-            m_results.values().clear();
-            std::move(vm.captures().begin(), vm.captures().end(), std::back_inserter(m_results.values()));
-            m_next_pos = (direction == MatchDirection::Forward) ? m_results[0].second : m_results[0].first;
-        }
-        else
-            m_program = nullptr;
+        if (not m_vm.exec(forward ? m_next_pos : m_begin, forward ? m_end : m_next_pos,
+                          m_subject_begin, m_subject_end, m_flags | additional_flags))
+            return false;
+
+        m_results.values().clear();
+        std::move(m_vm.captures().begin(), m_vm.captures().end(), std::back_inserter(m_results.values()));
+        m_next_pos = (direction == MatchDirection::Forward) ? m_results[0].second : m_results[0].first;
+        return true;
     }
 
-    const CompiledRegex* m_program = nullptr;
+    ThreadedRegexVM<Iterator, direction> m_vm;
     MatchResults<Iterator> m_results;
     Iterator m_next_pos{};
     const Iterator m_begin{};
diff --git a/src/selectors.cc b/src/selectors.cc
index 47aef03c..fc661c08 100644
--- a/src/selectors.cc
+++ b/src/selectors.cc
@@ -305,7 +305,7 @@ find_opening(Iterator pos, const Container& container,
         pos = res[0].first;
 
     using RegexIt = RegexIterator<Iterator, MatchDirection::Backward>;
-    for (auto match : RegexIt{container.begin(), pos, container.begin(), container.end(), opening})
+    for (auto&& match : RegexIt{container.begin(), pos, container.begin(), container.end(), opening})
     {
         if (nestable)
         {
@@ -923,8 +923,6 @@ Selection find_next_match(const Context& context, const Selection& sel, const Re
 template Selection find_next_match<MatchDirection::Forward>(const Context&, const Selection&, const Regex&, bool&);
 template Selection find_next_match<MatchDirection::Backward>(const Context&, const Selection&, const Regex&, bool&);
 
-using RegexIt = RegexIterator<BufferIterator>;
-
 void select_all_matches(SelectionList& selections, const Regex& regex, int capture)
 {
     const int mark_count = (int)regex.mark_count();
@@ -937,21 +935,19 @@ void select_all_matches(SelectionList& selections, const Regex& regex, int captu
     {
         auto sel_beg = buffer.iterator_at(sel.min());
         auto sel_end = utf8::next(buffer.iterator_at(sel.max()), buffer.end());
-        RegexIt re_it(sel_beg, sel_end, regex, match_flags(buffer, sel_beg, sel_end));
-        RegexIt re_end;
 
-        for (; re_it != re_end; ++re_it)
+        for (auto&& match : RegexIterator{sel_beg, sel_end, regex, match_flags(buffer, sel_beg, sel_end)})
         {
-            auto begin = (*re_it)[capture].first;
+            auto begin = match[capture].first;
             if (begin == sel_end)
                 continue;
-            auto end = (*re_it)[capture].second;
+            auto end = match[capture].second;
 
             CaptureList captures;
             captures.reserve(mark_count);
-            for (const auto& match : *re_it)
-                captures.push_back(buffer.string(match.first.coord(),
-                                                 match.second.coord()));
+            for (const auto& submatch : match)
+                captures.push_back(buffer.string(submatch.first.coord(),
+                                                 submatch.second.coord()));
 
             result.push_back(
                 keep_direction({ begin.coord(),
@@ -981,12 +977,9 @@ void split_selections(SelectionList& selections, const Regex& regex, int capture
         auto begin = buffer.iterator_at(sel.min());
         auto sel_end = utf8::next(buffer.iterator_at(sel.max()), buffer.end());
 
-        RegexIt re_it(begin, sel_end, regex, match_flags(buffer, begin, sel_end));
-        RegexIt re_end;
-
-        for (; re_it != re_end; ++re_it)
+        for (auto&& match : RegexIterator{begin, sel_end, regex, match_flags(buffer, begin, sel_end)})
         {
-            BufferIterator end = (*re_it)[capture].first;
+            BufferIterator end = match[capture].first;
             if (end == buf_end)
                 continue;
 
@@ -995,7 +988,7 @@ void split_selections(SelectionList& selections, const Regex& regex, int capture
                 auto sel_end = (begin == end) ? end : utf8::previous(end, begin);
                 result.push_back(keep_direction({ begin.coord(), sel_end.coord() }, sel));
             }
-            begin = (*re_it)[capture].second;
+            begin = match[capture].second;
         }
         if (begin.coord() <= sel.max())
             result.push_back(keep_direction({ begin.coord(), sel.max() }, sel));
diff --git a/src/shell_manager.cc b/src/shell_manager.cc
index 56fbfe38..4c0aded2 100644
--- a/src/shell_manager.cc
+++ b/src/shell_manager.cc
@@ -136,10 +136,9 @@ Vector<String> generate_env(StringView cmdline, const Context& context, const Sh
     static const Regex re(R"(\bkak_(\w+)\b)");
 
     Vector<String> kak_env;
-    for (RegexIterator<const char*> it{cmdline.begin(), cmdline.end(), re}, end;
-         it != end; ++it)
+    for (auto&& match : RegexIterator{cmdline.begin(), cmdline.end(), re})
     {
-        StringView name{(*it)[1].first, (*it)[1].second};
+        StringView name{match[1].first, match[1].second};
 
         auto match_name = [&](const String& s) {
             return s.substr(0_byte, name.length()) == name and