Selectors: add a basic select_matching selector for <([{]])> pairs

src/main.cc

@@ -354,6 +354,8 @@ std::unordered_map<char, std::function<void (Window& window, int count)>> keymap
     { 'b', [](Window& window, int count) { do { window.select(false, select_to_previous_word); } while(--count > 0); } },
     { 'B', [](Window& window, int count) { do { window.select(true, select_to_previous_word); } while(--count > 0); } },
     { '.', [](Window& window, int count) { do { window.select(false, select_line); } while(--count > 0); } },
+    { 'm', [](Window& window, int count) { window.select(false, select_matching); } },
+    { 'M', [](Window& window, int count) { window.select(true, select_matching); } },
     { '/', [](Window& window, int count) { do_search(window); } },
     { 'u', [](Window& window, int count) { do { if (not window.undo()) { print_status("nothing left to undo"); break; } } while(--count > 0); } },
     { 'U', [](Window& window, int count) { do { if (not window.redo()) { print_status("nothing left to redo"); break; } } while(--count > 0); } },

src/selectors.cc

@@ -1,8 +1,15 @@
 #include "selectors.hh"
 
+#include <algorithm>
+
 namespace Kakoune
 {
 
+static bool is_eol(char c)
+{
+    return c == '\n';
+}
+
 static bool is_blank(char c)
 {
     return c == ' ' or c == '\t' or c == '\n';
@@ -75,4 +82,53 @@ Selection move_select(Window& window, const BufferIterator& cursor, const Window
     return Selection(cursor, window.iterator_at(new_pos));
 }
 
+Selection select_matching(const BufferIterator& cursor)
+{
+    std::vector<char> matching_pairs = { '(', ')', '{', '}', '[', ']', '<', '>' };
+    BufferIterator it = cursor;
+    std::vector<char>::iterator match = matching_pairs.end();
+    while (not is_eol(*it))
+    {
+        match = std::find(matching_pairs.begin(), matching_pairs.end(), *it);
+        if (match != matching_pairs.end())
+            break;
+        ++it;
+    }
+    if (match == matching_pairs.end())
+        return Selection(cursor, cursor);
+
+    BufferIterator begin = it;
+
+    if (((match - matching_pairs.begin()) % 2) == 0)
+    {
+        int level = 0;
+        const char opening = *match;
+        const char closing = *(match+1);
+        while (not it.is_end())
+        {
+            if (*it == opening)
+                ++level;
+            else if (*it == closing and --level == 0)
+                return Selection(begin, it+1);
+
+            ++it;
+        }
+    }
+    else
+    {
+        int level = 0;
+        const char opening = *(match-1);
+        const char closing = *match;
+        while (not it.is_begin())
+        {
+            if (*it == closing)
+                ++level;
+            else if (*it == opening and --level == 0)
+                return Selection(begin, it);
+            --it;
+        }
+    }
+    return Selection(cursor, cursor);
+}
+
 }

src/selectors.hh

@@ -11,6 +11,7 @@ Selection select_to_next_word_end(const BufferIterator& cursor);
 Selection select_to_previous_word(const BufferIterator& cursor);
 Selection select_line(const BufferIterator& cursor);
 Selection move_select(Window& window, const BufferIterator& cursor, const WindowCoord& offset);
+Selection select_matching(const BufferIterator& cursor);
 
 }