Add basic support for colalias completion

src/color_registry.cc

@@ -36,6 +36,19 @@ void ColorRegistry::register_alias(const String& name, const String& colordesc,
                       it->second : parse_color_pair(colordesc);
 }
 
+CandidateList ColorRegistry::complete_alias_name(const String& prefix,
+                                                 ByteCount cursor_pos) const
+{
+    CandidateList res;
+    String real_prefix = prefix.substr(0, cursor_pos);
+    for (auto& alias : m_aliases)
+    {
+        if (prefix_match(alias.first, real_prefix))
+            res.push_back(alias.first);
+    }
+    return res;
+}
+
 ColorRegistry::ColorRegistry()
     : m_aliases{
         { "PrimarySelection", { Colors::Cyan, Colors::Blue } },

src/color_registry.hh

@@ -3,6 +3,7 @@
 
 #include "color.hh"
 #include "utils.hh"
+#include "completion.hh"
 
 #include <unordered_map>
 
@@ -18,6 +19,8 @@ public:
     void register_alias(const String& name, const String& colordesc,
                         bool override = false);
 
+    CandidateList complete_alias_name(const String& prefix,
+                                      ByteCount cursor_pos) const;
 private:
     std::unordered_map<String, ColorPair>    m_aliases;
 };

src/commands.cc

@@ -1113,13 +1113,20 @@ const CommandDesc try_catch_cmd = {
     }
 };
 
+static Completions complete_colalias(const Context&, CompletionFlags flags,
+                                     const String& prefix, ByteCount cursor_pos)
+{
+    return {0_byte, prefix.length(),
+            ColorRegistry::instance().complete_alias_name(prefix, cursor_pos)};
+}
+
 const CommandDesc define_color_alias_cmd = {
     "colalias",
     "ca",
     "colalias <name> <color>: set <name> to refer to color <color> (which can be an alias itself)",
     ParameterDesc{ SwitchMap{}, ParameterDesc::Flags::None, 2, 2 },
     CommandFlags::None,
-    CommandCompleter{},
+    PerArgumentCommandCompleter({ complete_colalias, complete_colalias }),
     [](const ParametersParser& parser, Context& context)
     {
         ColorRegistry::instance().register_alias(parser[0], parser[1], true);