Refactor number_line higlighter, use a switch to higlhight the cursor line

README.asciidoc

@@ -637,8 +637,9 @@ general highlighters are:
        <option_name>.
  * +show_matching+: highlight matching char of the character under the selections
        cursor using +MatchingChar+ face.
- * +number_lines <-relative>+: show line numbers. The -relative switch will enable relative
+ * +number_lines <-relative> <-hlcursor>+: show line numbers. The -relative switch
-       line numbers.
+       will show line numbers to main cursor line, the -hlcursor switch will
+       highlight the cursor line with a separate face..
  * +fill <face>+: fill using given face, mostly useful with the +regions+ highlighter
        (see below)
 

src/face_registry.cc

@@ -96,7 +96,7 @@ FaceRegistry::FaceRegistry()
         { "PrimaryCursor", Face{ Colors::Black, Colors::White } },
         { "SecondaryCursor", Face{ Colors::Black, Colors::White } },
         { "LineNumbers", Face{ Colors::Default, Colors::Default } },
-        { "LineNumberAbsolute", Face{ Colors::Black, Colors::Blue } },
+        { "LineNumberCursor", Face{ Colors::Default, Colors::Default, Attribute::Reverse } },
         { "MenuForeground", Face{ Colors::White, Colors::Blue } },
         { "MenuBackground", Face{ Colors::Blue, Colors::White } },
         { "Information", Face{ Colors::Black, Colors::Yellow } },

src/highlighters.cc

@@ -594,11 +594,12 @@ void show_whitespaces(const Context& context, HighlightFlags flags, DisplayBuffe
     }
 }
 
-template<bool relative>
+template<bool relative, bool hl_cursor_line>
-void show_line_numbers(const Context& context, HighlightFlags flags, DisplayBuffer& display_buffer, BufferRange)
+void show_line_numbers(const Context& context, HighlightFlags flags,
+                       DisplayBuffer& display_buffer, BufferRange)
 {
     const Face face = get_face("LineNumbers");
-    const Face face_absolute = get_face("LineNumberAbsolute");
+    const Face face_absolute = get_face("LineNumberCursor");
     LineCount last_line = context.buffer().line_count();
     int digit_count = 0;
     for (LineCount c = last_line; c > 0; c /= 10)
@@ -609,41 +610,40 @@ void show_line_numbers(const Context& context, HighlightFlags flags, DisplayBuff
     int main_selection = (int)context.selections().main().cursor().line + 1;
     for (auto& line : display_buffer.lines())
     {
-        int current_line = (int)line.range().first.line + 1;
+        const int current_line = (int)line.range().first.line + 1;
+        const bool is_cursor_line = main_selection == current_line;
+        const int line_to_format = (relative and not is_cursor_line) ?
+                                   current_line - main_selection : current_line;
         char buffer[16];
-        if (relative)
+        snprintf(buffer, 16, format, line_to_format);
-        {
+        DisplayAtom atom{buffer};
-            if (main_selection == current_line)
+        atom.face = (hl_cursor_line and is_cursor_line) ? face_absolute : face;
-            {
+        line.insert(line.begin(), std::move(atom));
-                snprintf(buffer, 16, format, current_line);
-                DisplayAtom atom{buffer};
-                atom.face = face_absolute;
-                line.insert(line.begin(), std::move(atom));
-            }
-            else {
-                snprintf(buffer, 16, format, current_line - main_selection);
-                DisplayAtom atom{buffer};
-                atom.face = face;
-                line.insert(line.begin(), std::move(atom));
-            }
-        }
-        else {
-            snprintf(buffer, 16, format, current_line);
-            DisplayAtom atom{buffer};
-            (main_selection == current_line) ? atom.face = face_absolute
-                                                : atom.face = face;
-            line.insert(line.begin(), std::move(atom));
-        }
     }
 }
 
 HighlighterAndId number_lines_factory(HighlighterParameters params)
 {
-    if (params.size() > 1)
+    static const ParameterDesc param_desc{
-        throw runtime_error("wrong parameter count");
+        { { "relative", { false, "" } },
+          { "hlcursor", { false, "" } } },
+        ParameterDesc::Flags::None, 0, 0
+    };
+    ParametersParser parser(params, param_desc);
 
-    return (params.size() == 1 && params[0] == "-relative") ? HighlighterAndId("number_lines_relative", make_simple_highlighter(show_line_numbers<true>))
+    constexpr struct {
-                                                               : HighlighterAndId("number_lines", make_simple_highlighter(show_line_numbers<false>));
+        StringView name;
+        void (*func)(const Context&, HighlightFlags, DisplayBuffer&, BufferRange);
+    } funcs[] = {
+        { "number_lines", show_line_numbers<false, false> },
+        { "number_lines", show_line_numbers<false, true> },
+        { "number_lines_relative", show_line_numbers<true, false> },
+        { "number_lines_relative", show_line_numbers<true, true> },
+    };
+    const int index = (parser.get_switch("relative") ? 1 : 0) * 2 +
+                      (parser.get_switch("hlcursor") ? 1 : 0);
+
+    return {funcs[index].name.str(), make_simple_highlighter(funcs[index].func)};
 }
 
 void show_matching_char(const Context& context, HighlightFlags flags, DisplayBuffer& display_buffer, BufferRange)
@@ -1239,7 +1239,7 @@ void register_highlighters()
         "number_lines",
         { number_lines_factory,
           "Display line numbers \n"
-          "Parameters: -relative" } });
+          "Parameters: -relative, -hlcursor\n" } });
     registry.append({
         "show_matching",
         { simple_factory("show_matching", show_matching_char),