add an OptionManager class and use it to manage tabstops

OptionManager map names to options, and may delegate option resolution
to it's parent if it does not contains the asked for option. That way
Buffers can override global options, and Windows can override Buffer
options.

src/buffer.cc

@@ -26,7 +26,8 @@ Buffer::Buffer(const std::string& name, Type type,
                const String& initial_content)
     : m_name(name), m_type(type),
       m_history(1), m_history_cursor(m_history.begin()),
-      m_last_save_undo_index(0)
+      m_last_save_undo_index(0),
+      m_option_manager(GlobalOptionManager::instance())
 {
     BufferManager::instance().register_buffer(this);
     if (not initial_content.empty())

src/buffer.hh

@@ -7,6 +7,7 @@
 #include <memory>
 
 #include "line_and_column.hh"
+#include "option_manager.hh"
 
 namespace Kakoune
 {
@@ -173,6 +174,8 @@ public:
 
     const String& line_content(size_t l) const { return m_lines[l].content; }
 
+    OptionManager& option_manager() { return m_option_manager; }
+
 private:
     friend class BufferIterator;
 
@@ -210,6 +213,8 @@ private:
     size_t m_last_save_undo_index;
 
     std::vector<ModificationListener*> m_modification_listeners;
+
+    OptionManager m_option_manager;
 };
 
 inline Modification Modification::make_erase(BufferIterator begin,

src/filters.cc

@@ -39,7 +39,7 @@ void cleanup_whitespaces(Buffer& buffer, Modification& modification)
 
 void expand_tabulations(Buffer& buffer, Modification& modification)
 {
-    const int tabstop = 8;
+    const int tabstop = buffer.option_manager()["tabstop"];
     if (modification.type == Modification::Insert and
         modification.content == "\t")
     {

src/highlighters.cc

@@ -10,6 +10,8 @@
 namespace Kakoune
 {
 
+using namespace std::placeholders;
+
 void colorize_regex_range(DisplayBuffer& display_buffer,
                           const BufferIterator& range_begin,
                           const BufferIterator& range_end,
@@ -97,13 +99,13 @@ HighlighterAndId colorize_regex_factory(Window& window,
 
     std::string id = "colre'" + params[0] + "'";
 
-    return HighlighterAndId(id, std::bind(colorize_regex, std::placeholders::_1,
+    return HighlighterAndId(id, std::bind(colorize_regex, _1,
                                           ex, fg_color, bg_color));
 }
 
-void expand_tabulations(DisplayBuffer& display_buffer)
+void expand_tabulations(Window& window, DisplayBuffer& display_buffer)
 {
-    const int tabstop = 8;
+    const int tabstop = window.option_manager()["tabstop"];
     for (auto atom_it = display_buffer.begin();
          atom_it != display_buffer.end(); ++atom_it)
     {
@@ -289,7 +291,6 @@ public:
     HighlighterAndId operator()(Window& window,
                                 const HighlighterParameters& params) const
     {
-        using namespace std::placeholders;
         return HighlighterAndId(m_id, std::bind(highlighter_func, std::ref(window), _1));
     }
 private:
@@ -310,7 +311,7 @@ void register_highlighters()
     HighlighterRegistry& registry = HighlighterRegistry::instance();
 
     registry.register_factory("highlight_selections", WindowHighlighterFactory<highlight_selections>("highlight_selections"));
-    registry.register_factory("expand_tabs", SimpleHighlighterFactory<expand_tabulations>("expand_tabs"));
+    registry.register_factory("expand_tabs", WindowHighlighterFactory<expand_tabulations>("expand_tabs"));
     registry.register_factory("number_lines", SimpleHighlighterFactory<show_line_numbers>("number_lines"));
     registry.register_factory("regex", colorize_regex_factory);
     registry.register_factory("group", highlighter_group_factory);

src/main.cc

@@ -12,6 +12,7 @@
 #include "filters.hh"
 #include "filter_registry.hh"
 #include "hook_manager.hh"
+#include "option_manager.hh"
 #include "context.hh"
 #include "ncurses.hh"
 
@@ -918,6 +919,7 @@ int main(int argc, char* argv[])
     HighlighterRegistry highlighter_registry;
     FilterRegistry      filter_registry;
     GlobalHookManager   hook_manager;
+    GlobalOptionManager option_manager;
 
     run_unit_tests();
 

src/option_manager.cc

@@ -0,0 +1,21 @@
+#include "option_manager.hh"
+
+#include <sstream>
+
+namespace Kakoune
+{
+
+std::string int_to_str(int value)
+{
+    std::ostringstream oss;
+    oss << value;
+    return oss.str();
+}
+
+GlobalOptionManager::GlobalOptionManager()
+    : OptionManager()
+{
+    (*this)["tabstop"] = 8;
+}
+
+}

src/option_manager.hh

@@ -0,0 +1,84 @@
+#ifndef option_manager_hh_INCLUDED
+#define option_manager_hh_INCLUDED
+
+#include "utils.hh"
+#include "exception.hh"
+
+#include <unordered_map>
+
+namespace Kakoune
+{
+
+struct option_not_found : public runtime_error
+{
+    option_not_found(const std::string& name)
+        : runtime_error("option not found: " + name) {}
+};
+
+std::string int_to_str(int value);
+
+class Option
+{
+public:
+    Option() {}
+    explicit Option(int value) : m_value(int_to_str(value)) {}
+    explicit Option(const std::string& value) : m_value(value) {}
+
+    Option& operator=(int value) { m_value = int_to_str(value); return *this; }
+    Option& operator=(const std::string& value) { m_value = value; return *this; }
+
+    operator int() const { return atoi(m_value.c_str()); }
+    operator std::string() const { return m_value; }
+private:
+    std::string m_value;
+};
+
+class OptionManager
+{
+public:
+    OptionManager(OptionManager& parent)
+        : m_parent(&parent) {}
+
+    Option& operator[] (const std::string& name)
+    {
+        auto it = m_options.find(name);
+        if (it != m_options.end())
+            return it->second;
+        else if (m_parent)
+            return (*m_parent)[name];
+        else
+            return m_options[name];
+    }
+
+    const Option& operator[] (const std::string& name) const
+    {
+        auto it = m_options.find(name);
+        if (it != m_options.end())
+            return it->second;
+        else if (m_parent)
+            return (*m_parent)[name];
+        else
+            throw option_not_found(name);
+    }
+
+private:
+    OptionManager()
+        : m_parent(nullptr) {}
+    // the only one allowed to construct a root option manager
+    friend class GlobalOptionManager;
+
+    std::unordered_map<std::string, Option> m_options;
+    OptionManager* m_parent;
+};
+
+class GlobalOptionManager : public OptionManager,
+                            public Singleton<GlobalOptionManager>
+{
+public:
+    GlobalOptionManager();
+};
+
+
+}
+
+#endif // option_manager_hh_INCLUDED

src/window.cc

@@ -14,7 +14,8 @@ namespace Kakoune
 Window::Window(Buffer& buffer)
     : Editor(buffer),
       m_position(0, 0),
-      m_dimensions(0, 0)
+      m_dimensions(0, 0),
+      m_option_manager(buffer.option_manager())
 {
     HighlighterRegistry& registry = HighlighterRegistry::instance();
 

src/window.hh

@@ -9,6 +9,7 @@
 #include "highlighter.hh"
 #include "highlighter_group.hh"
 #include "hook_manager.hh"
+#include "option_manager.hh"
 
 namespace Kakoune
 {
@@ -38,7 +39,8 @@ public:
 
     HighlighterGroup& highlighters() { return m_highlighters; }
 
-    HookManager& hook_manager() { return m_hook_manager; }
+    HookManager&   hook_manager()   { return m_hook_manager; }
+    OptionManager& option_manager() { return m_option_manager; }
 
 private:
     friend class Buffer;
@@ -57,6 +59,7 @@ private:
     HighlighterGroup m_highlighters;
 
     HookManager      m_hook_manager;
+    OptionManager    m_option_manager;
 };
 
 }