Change completion_extra_word_char to be a list of codepoints instead of a string

src/insert_completer.cc

@@ -79,7 +79,7 @@ WordDB& get_word_db(const Buffer& buffer)
 template<bool other_buffers>
 InsertCompletion complete_word(const SelectionList& sels, const OptionManager& options)
 {
-    StringView extra_word_char = options["completion_extra_word_char"].get<String>();
+    auto& extra_word_char = options["completion_extra_word_char"].get<Vector<Codepoint, MemoryDomain::Options>>();
     auto is_word_pred = [extra_word_char](Codepoint c) { return is_word(c) or contains(extra_word_char, c); };
 
     const Buffer& buffer = sels.buffer();

src/main.cc

@@ -251,7 +251,7 @@ static void check_timeout(const int& timeout)
         throw runtime_error{"the minimum acceptable timeout is 50 milliseconds"};
 }
 
-static void check_extra_word_char(const String& extra_chars)
+static void check_extra_word_char(const Vector<Codepoint, MemoryDomain::Options>& extra_chars)
 {
     if (contains_that(extra_chars, is_blank))
         throw runtime_error{"blanks are not accepted for extra completion characters"};
@@ -324,10 +324,10 @@ void register_options()
 
     reg.declare_option("debug", "various debug flags", DebugFlags::None);
     reg.declare_option("readonly", "prevent buffers from being modified", false);
-    reg.declare_option<String, check_extra_word_char>(
+    reg.declare_option<Vector<Codepoint, MemoryDomain::Options>, check_extra_word_char>(
         "completion_extra_word_char",
         "Additional characters to be considered as words for insert completion",
-        ""_str);
+        {});
 }
 
 static Client* local_client = nullptr;

src/option_types.hh

@@ -57,6 +57,15 @@ inline void option_from_string(StringView str, bool& opt)
 }
 constexpr StringView option_type_name(Meta::Type<bool>) { return "bool"; }
 
+inline String option_to_string(Codepoint opt) { return to_string(opt); }
+inline void option_from_string(StringView str, Codepoint& opt)
+{
+    if (str.char_length() != 1)
+        throw runtime_error{format("'{}' is not a single codepoint", str)};
+    opt = str[0_char];
+}
+constexpr StringView option_type_name(Meta::Type<Codepoint>) { return "codepoint"; }
+
 constexpr char list_separator = ':';
 
 template<typename T, MemoryDomain domain>

src/word_db.cc

@@ -30,13 +30,9 @@ static WordList get_words(StringView content, ConstArrayView<Codepoint> extra_wo
     return res;
 }
 
-static Vector<Codepoint> get_extra_word_chars(const Buffer& buffer)
+static ConstArrayView<Codepoint> get_extra_word_chars(const Buffer& buffer)
 {
-    auto& str = buffer.options()["completion_extra_word_char"].get<String>();
-    Vector<Codepoint> res;
-    for (utf8::iterator<const char*> it{str.begin(), str}; it != str.end(); ++it)
-        res.push_back(*it);
-    return res;
+    return buffer.options()["completion_extra_word_char"].get<Vector<Codepoint, MemoryDomain::Options>>();
 }
 
 void WordDB::add_words(StringView line)