Regex are overkill for shell manager env vars, we just need exact match or prefix match

src/main.cc

@@ -55,92 +55,93 @@ void register_env_vars()
 {
     static const struct {
         const char* name;
+        bool prefix;
         String (*func)(StringView, const Context&);
     } env_vars[] = { {
-            "bufname",
+            "bufname", false,
             [](StringView name, const Context& context) -> String
             { return context.buffer().display_name(); }
         }, {
-            "buffile",
+            "buffile", false,
             [](StringView name, const Context& context) -> String
             { return context.buffer().name(); }
         }, {
-            "buflist",
+            "buflist", false,
             [](StringView name, const Context& context)
             { return join(transformed(BufferManager::instance(),
                                       [](const SafePtr<Buffer>& b)
                                       { return b->display_name(); }), ':'); }
         }, {
-            "timestamp",
+            "timestamp", false,
             [](StringView name, const Context& context) -> String
             { return to_string(context.buffer().timestamp()); }
         }, {
-            "selection",
+            "selection", false,
             [](StringView name, const Context& context)
             { const Selection& sel = context.selections().main();
               return content(context.buffer(), sel); }
         }, {
-            "selections",
+            "selections", false,
             [](StringView name, const Context& context)
             { return join(context.selections_content(), ':'); }
         }, {
-            "runtime",
+            "runtime", false,
             [](StringView name, const Context& context)
             { return runtime_directory(); }
         }, {
-            "opt_.+",
+            "opt_", true,
             [](StringView name, const Context& context)
             { return context.options()[name.substr(4_byte)].get_as_string(); }
         }, {
-            "reg_.+",
+            "reg_", true,
             [](StringView name, const Context& context)
             { return context.main_sel_register_value(name.substr(4_byte)).str(); }
         }, {
-            "client_env_.+",
+            "client_env_", true,
             [](StringView name, const Context& context)
             { return context.client().get_env_var(name.substr(11_byte)).str(); }
         }, {
-            "session",
+            "session", false,
             [](StringView name, const Context& context) -> String
             { return Server::instance().session(); }
         }, {
-            "client",
+            "client", false,
             [](StringView name, const Context& context) -> String
             { return context.name(); }
         }, {
-            "cursor_line",
+            "cursor_line", false,
             [](StringView name, const Context& context) -> String
             { return to_string(context.selections().main().cursor().line + 1); }
         }, {
-            "cursor_column",
+            "cursor_column", false,
             [](StringView name, const Context& context) -> String
             { return to_string(context.selections().main().cursor().column + 1); }
         }, {
-            "cursor_char_column",
+            "cursor_char_column", false,
             [](StringView name, const Context& context) -> String
             { auto coord = context.selections().main().cursor();
               return to_string(context.buffer()[coord.line].char_count_to(coord.column) + 1); }
         }, {
-            "selection_desc",
+            "selection_desc", false,
             [](StringView name, const Context& context)
             { return selection_to_string(context.selections().main()); }
         }, {
-            "selections_desc",
+            "selections_desc", false,
             [](StringView name, const Context& context)
             { return selection_list_to_string(context.selections()); }
         }, {
-            "window_width",
+            "window_width", false,
             [](StringView name, const Context& context) -> String
             { return to_string(context.window().dimensions().column); }
         }, {
-            "window_height",
+            "window_height", false,
             [](StringView name, const Context& context) -> String
             { return to_string(context.window().dimensions().line); }
     } };
 
     ShellManager& shell_manager = ShellManager::instance();
     for (auto& env_var : env_vars)
-        shell_manager.register_env_var(env_var.name, env_var.func);
+        shell_manager.register_env_var(env_var.name, env_var.prefix, env_var.func);
 }
 
 void register_registers()

src/shell_manager.cc

@@ -135,22 +135,24 @@ std::pair<String, int> ShellManager::eval(
     return {};
 }
 
-void ShellManager::register_env_var(StringView regex,
+void ShellManager::register_env_var(StringView str, bool prefix,
                                     EnvVarRetriever retriever)
 {
-    m_env_vars.push_back({ Regex{regex}, std::move(retriever) });
+    m_env_vars.push_back({ str.str(), prefix, std::move(retriever) });
 }
 
 String ShellManager::get_val(StringView name, const Context& context) const
 {
     auto env_var = std::find_if(
         m_env_vars.begin(), m_env_vars.end(),
-        [name](const std::pair<Regex, EnvVarRetriever>& pair)
+        [name](const EnvVarDesc& desc) {
-        { return regex_match(name.begin(), name.end(), pair.first); });
+            return desc.prefix ? prefix_match(name, desc.str) : name == desc.str;
+        });
 
     if (env_var == m_env_vars.end())
         throw runtime_error("no such env var: " + name);
-    return env_var->second(name, context);
+
+    return env_var->func(name, context);
 }
 
 }

src/shell_manager.hh

@@ -33,11 +33,12 @@ public:
                                 ConstArrayView<String> params = {},
                                 const EnvVarMap& env_vars = EnvVarMap{});
 
-    void register_env_var(StringView regex, EnvVarRetriever retriever);
+    void register_env_var(StringView str, bool prefix, EnvVarRetriever retriever);
     String get_val(StringView name, const Context& context) const;
 
 private:
-    Vector<std::pair<Regex, EnvVarRetriever>> m_env_vars;
+    struct EnvVarDesc { String str; bool prefix; EnvVarRetriever func; };
+    Vector<EnvVarDesc> m_env_vars;
 };
 
 template<> struct WithBitOps<ShellManager::Flags> : std::true_type {};