Shifts essential modifiers up to the Keyboard class.

I had forgotten that mappers are not exposed.

Inputs/Keyboard.cpp

@@ -10,13 +10,14 @@
 
 using namespace Inputs;
 
-Keyboard::Keyboard() {
+Keyboard::Keyboard(const std::set<Key> &essential_modifiers) : essential_modifiers_(essential_modifiers) {
 	for(int k = 0; k < int(Key::Help); ++k) {
 		observed_keys_.insert(Key(k));
 	}
 }
 
-Keyboard::Keyboard(const std::set<Key> &observed_keys) : observed_keys_(observed_keys), is_exclusive_(false) {}
+Keyboard::Keyboard(const std::set<Key> &observed_keys, const std::set<Key> &essential_modifiers) :
+	observed_keys_(observed_keys), essential_modifiers_(essential_modifiers), is_exclusive_(false) {}
 
 void Keyboard::set_key_pressed(Key key, char value, bool is_pressed) {
 	std::size_t key_offset = static_cast<std::size_t>(key);
@@ -28,6 +29,10 @@ void Keyboard::set_key_pressed(Key key, char value, bool is_pressed) {
 	if(delegate_) delegate_->keyboard_did_change_key(this, key, is_pressed);
 }
 
+const std::set<Inputs::Keyboard::Key> &Keyboard::get_essential_modifiers() {
+	return essential_modifiers_;
+}
+
 void Keyboard::reset_all_keys() {
 	std::fill(key_states_.begin(), key_states_.end(), false);
 	if(delegate_) delegate_->reset_all_keys(this);

Inputs/Keyboard.hpp

@@ -39,10 +39,10 @@ class Keyboard {
 		};
 
 		/// Constructs a Keyboard that declares itself to observe all keys.
-		Keyboard();
+		Keyboard(const std::set<Key> &essential_modifiers = {});
 
 		/// Constructs a Keyboard that declares itself to observe only members of @c observed_keys.
-		Keyboard(const std::set<Key> &observed_keys);
+		Keyboard(const std::set<Key> &observed_keys, const std::set<Key> &essential_modifiers);
 
 		// Host interface.
 		virtual void set_key_pressed(Key key, char value, bool is_pressed);
@@ -51,10 +51,18 @@ class Keyboard {
 		/// @returns a set of all Keys that this keyboard responds to.
 		virtual const std::set<Key> &observed_keys();
 
-		/*
+		/// @returns the list of modifiers that this keyboard considers 'essential' (i.e. both mapped and highly used).
+		virtual const std::set<Inputs::Keyboard::Key> &get_essential_modifiers();
+
+		/*!
 			@returns @c true if this keyboard, on its original machine, looked
 			like a complete keyboard — i.e. if a user would expect this keyboard
 			to be the only thing a real keyboard maps to.
+
+			So this would be true of something like the Amstrad CPC, which has a full
+			keyboard, but it would be false of something like the Sega Master System
+			which has some buttons that you'd expect an emulator to map to its host
+			keyboard but which does not offer a full keyboard.
 		*/
 		virtual bool is_exclusive();
 
@@ -68,6 +76,7 @@ class Keyboard {
 
 	private:
 		std::set<Key> observed_keys_;
+		std::set<Key> essential_modifiers_;
 		std::vector<bool> key_states_;
 		Delegate *delegate_ = nullptr;
 		bool is_exclusive_ = true;

Machines/Apple/Macintosh/Keyboard.cpp

@@ -86,13 +86,3 @@ uint16_t KeyboardMapper::mapped_key_for_key(Inputs::Keyboard::Key key) {
 #undef Bind
 	}
 }
-
-std::set<Inputs::Keyboard::Key> KeyboardMapper::get_essential_modifiers() {
-	// Control is fairly optional for a Mac, but option, meta and shift
-	// are essential.
-	return {
-		Inputs::Keyboard::Key::LeftShift, Inputs::Keyboard::Key::RightShift,
-		Inputs::Keyboard::Key::LeftOption, Inputs::Keyboard::Key::RightOption,
-		Inputs::Keyboard::Key::LeftMeta, Inputs::Keyboard::Key::RightMeta,
-	};
-}

Machines/Apple/Macintosh/Keyboard.hpp

@@ -292,7 +292,6 @@ class Keyboard {
 */
 class KeyboardMapper: public KeyboardMachine::MappedMachine::KeyboardMapper {
 	uint16_t mapped_key_for_key(Inputs::Keyboard::Key key) final;
-	std::set<Inputs::Keyboard::Key> get_essential_modifiers() final;
 };
 
 }

Machines/Apple/Macintosh/Macintosh.cpp

@@ -78,6 +78,11 @@ template <Analyser::Static::Macintosh::Target::Model model> class ConcreteMachin
 		using Target = Analyser::Static::Macintosh::Target;
 
 		ConcreteMachine(const Target &target, const ROMMachine::ROMFetcher &rom_fetcher) :
+			KeyboardMachine::MappedMachine({
+				Inputs::Keyboard::Key::LeftShift, Inputs::Keyboard::Key::RightShift,
+				Inputs::Keyboard::Key::LeftOption, Inputs::Keyboard::Key::RightOption,
+				Inputs::Keyboard::Key::LeftMeta, Inputs::Keyboard::Key::RightMeta,
+			}),
 		 	mc68000_(*this),
 		 	iwm_(CLOCK_RATE),
 		 	video_(audio_, drive_speed_accumulator_),

Machines/KeyboardMachine.cpp

@@ -10,7 +10,7 @@
 
 using namespace KeyboardMachine;
 
-MappedMachine::MappedMachine() {
+MappedMachine::MappedMachine(const std::set<Inputs::Keyboard::Key> &essential_modifiers) : keyboard_(essential_modifiers) {
 	keyboard_.set_delegate(this);
 }
 

Machines/KeyboardMachine.hpp

@@ -57,7 +57,7 @@ class Machine: public KeyActions {
 */
 class MappedMachine: public Inputs::Keyboard::Delegate, public Machine {
 	public:
-		MappedMachine();
+		MappedMachine(const std::set<Inputs::Keyboard::Key> &essential_modifiers = {});
 
 		/*!
 			A keyboard mapper attempts to provide a physical mapping between host keys and emulated keys.
@@ -66,7 +66,6 @@ class MappedMachine: public Inputs::Keyboard::Delegate, public Machine {
 		class KeyboardMapper {
 			public:
 				virtual uint16_t mapped_key_for_key(Inputs::Keyboard::Key key) = 0;
-				virtual std::set<Inputs::Keyboard::Key> get_essential_modifiers() { return {}; }
 		};
 
 		/// Terminates a key sequence from the character mapper.

Machines/MasterSystem/MasterSystem.cpp

@@ -101,7 +101,7 @@ class ConcreteMachine:
 				audio_queue_,
 				sn76489_divider),
 			speaker_(sn76489_),
-			keyboard_({Inputs::Keyboard::Key::Enter, Inputs::Keyboard::Key::Escape}) {
+			keyboard_({Inputs::Keyboard::Key::Enter, Inputs::Keyboard::Key::Escape}, {}) {
 			// Pick the clock rate based on the region.
 			const double clock_rate = target.region == Target::Region::Europe ? 3546893.0 : 3579540.0;
 			speaker_.set_input_rate(static_cast<float>(clock_rate / sn76489_divider));