select/split interpret count parameter as the capture group to use

count being 0 by default, we use the whole match, but we can now
specify to use capture 1 with 1s<regex><ret>.

3 files changed, 21 insertions, 13 deletions

diff --git a/src/normal.cc b/src/normal.cc
index 009a2224..54b062c1 100644
--- a/src/normal.cc
+++ b/src/normal.cc
@@ -704,26 +704,28 @@ void use_selection_as_search_pattern(Context& context, NormalParams params)
 void select_regex(Context& context, NormalParams params)
 {
     const char reg = to_lower(params.reg ? params.reg : '/');
-    regex_prompt(context, "select:", [reg](Regex ex, PromptEvent event, Context& context) {
+    unsigned capture = (unsigned)params.count;
+    regex_prompt(context, "select:", [reg, capture](Regex ex, PromptEvent event, Context& context) {
         if (ex.empty())
             ex = Regex{context.main_sel_register_value(reg)};
         else if (event == PromptEvent::Validate)
             RegisterManager::instance()[reg] = ex.str();
         if (not ex.empty() and not ex.str().empty())
-            select_all_matches(context.selections(), ex);
+            select_all_matches(context.selections(), ex, capture);
     });
 }
 
 void split_regex(Context& context, NormalParams params)
 {
     const char reg = to_lower(params.reg ? params.reg : '/');
-    regex_prompt(context, "split:", [reg](Regex ex, PromptEvent event, Context& context) {
+    unsigned capture = (unsigned)params.count;
+    regex_prompt(context, "split:", [reg, capture](Regex ex, PromptEvent event, Context& context) {
         if (ex.empty())
             ex = Regex{context.main_sel_register_value(reg)};
         else if (event == PromptEvent::Validate)
             RegisterManager::instance()[reg] = ex.str();
         if (not ex.empty() and not ex.str().empty())
-            split_selections(context.selections(), ex);
+            split_selections(context.selections(), ex, capture);
     });
 }
 
diff --git a/src/selectors.cc b/src/selectors.cc
index 524ff9e1..c86d2749 100644
--- a/src/selectors.cc
+++ b/src/selectors.cc
@@ -560,8 +560,12 @@ void select_buffer(SelectionList& selections)
 
 using RegexIt = RegexIterator<BufferIterator>;
 
-void select_all_matches(SelectionList& selections, const Regex& regex)
+void select_all_matches(SelectionList& selections, const Regex& regex, unsigned capture)
 {
+    const unsigned mark_count = regex.mark_count();
+    if (capture > mark_count)
+        throw runtime_error("invalid capture number");
+
     Vector<Selection> result;
     auto& buffer = selections.buffer();
     for (auto& sel : selections)
@@ -570,13 +574,12 @@ void select_all_matches(SelectionList& selections, const Regex& regex)
         RegexIt re_it(buffer.iterator_at(sel.min()), sel_end, regex);
         RegexIt re_end;
 
-        const unsigned mark_count = regex.mark_count();
         for (; re_it != re_end; ++re_it)
         {
-            auto begin = ensure_char_start(buffer, (*re_it)[0].first);
+            auto begin = ensure_char_start(buffer, (*re_it)[capture].first);
             if (begin == sel_end)
                 continue;
-            auto end = ensure_char_start(buffer, (*re_it)[0].second);
+            auto end = ensure_char_start(buffer, (*re_it)[capture].second);
 
             CaptureList captures;
             captures.reserve(mark_count);
@@ -598,8 +601,11 @@ void select_all_matches(SelectionList& selections, const Regex& regex)
     selections = SelectionList{buffer, std::move(result)};
 }
 
-void split_selections(SelectionList& selections, const Regex& regex)
+void split_selections(SelectionList& selections, const Regex& regex, unsigned capture)
 {
+    if (capture > regex.mark_count())
+        throw runtime_error("invalid capture number");
+
     Vector<Selection> result;
     auto& buffer = selections.buffer();
     auto buf_end = buffer.end();
@@ -612,13 +618,13 @@ void split_selections(SelectionList& selections, const Regex& regex)
 
         for (; re_it != re_end; ++re_it)
         {
-            BufferIterator end = (*re_it)[0].first;
+            BufferIterator end = (*re_it)[capture].first;
             if (end == buf_end)
                 continue;
 
             end = ensure_char_start(buffer, end);
             result.push_back(keep_direction({ begin.coord(), (begin == end) ? end.coord() : utf8::previous(end, begin).coord() }, sel));
-            begin = ensure_char_start(buffer, (*re_it)[0].second);
+            begin = ensure_char_start(buffer, (*re_it)[capture].second);
         }
         if (begin.coord() <= sel.max())
             result.push_back(keep_direction({ begin.coord(), sel.max() }, sel));
diff --git a/src/selectors.hh b/src/selectors.hh
index 7809344f..fff025fc 100644
--- a/src/selectors.hh
+++ b/src/selectors.hh
@@ -292,8 +292,8 @@ Selection find_next_match(const Buffer& buffer, const Selection& sel, const Rege
     return {begin.coord(), end.coord(), std::move(captures)};
 }
 
-void select_all_matches(SelectionList& selections, const Regex& regex);
-void split_selections(SelectionList& selections, const Regex& separator_regex);
+void select_all_matches(SelectionList& selections, const Regex& regex, unsigned capture = 0);
+void split_selections(SelectionList& selections, const Regex& separator_regex, unsigned capture = 0);
 
 struct MatchingPair { Codepoint opening, closing; };
 Selection select_surrounding(const Buffer& buffer, const Selection& selection,