enum class InputKey {
    a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z,

    SPACE,
    GRAVE_ACCENT,
    TILDE,

    ONE, TWO, THREE, FOUR, FIVE, SIX, SEVEN, EIGHT, NINE, ZERO,
    MINUS, EQUAL,

    EXCLAMATION_POINT, AT_SIGN, NUMBER_SIGN, DOLLAR_SIGN, PERCENT_SIGN,
    CARET, AMPERSAND, ASTERISK, LEFT_PARENTHESIS, RIGHT_PARENTHESIS,
    UNDERSCORE, PLUS,

    LEFT_SQUARE_BRACKET, RIGHT_SQUARE_BRACKET,
    LEFT_CURLY_BRACKET, RIGHT_CURLY_BRACKET,

    COMMA, PERIOD, LESS_THAN, GREATER_THAN,

    CAPS_LOCK, ESCAPE, ENTER, TAB, BACKSPACE, INSERT, DELETE,

    RIGHT, LEFT, UP, DOWN,

    SLASH, QUESTION_MARK, BACKSLASH, PIPE,
    COLON, SEMICOLON, SINGLE_QUOTE, DOUBLE_QUOTE,

    LEFT_SHIFT, RIGHT_SHIFT,
    LEFT_CONTROL, RIGHT_CONTROL,
    LEFT_ALT, RIGHT_ALT,
    LEFT_SUPER, RIGHT_SUPER,

    FUNCTION_KEY, MENU_KEY,

    LEFT_MOUSE_BUTTON, RIGHT_MOUSE_BUTTON, MIDDLE_MOUSE_BUTTON,
    SCROLL_UP, SCROLL_DOWN,

    DUMMY
};

struct InputKeyState {
    std::unordered_map<InputKey, bool> input_key_to_is_pressed;
    std::unordered_map<InputKey, bool> input_key_to_is_pressed_prev;
    std::unordered_map<InputKey, bool> input_key_to_just_pressed;
};

  component |= CatchEvent([&](Event event) {
...
}

struct Event {

...

  // --- Arrow ---
  static const Event ArrowLeft;
  static const Event ArrowRight;
  static const Event ArrowUp;
  static const Event ArrowDown;

  static const Event ArrowLeftCtrl;
  static const Event ArrowRightCtrl;
  static const Event ArrowUpCtrl;
  static const Event ArrowDownCtrl;

  // --- Other ---
  static const Event Backspace;
  static const Event Delete;
  static const Event Return;
  static const Event Escape;
  static const Event Tab;
  static const Event TabReverse;

  // --- Navigation keys ---
  static const Event Insert;
  static const Event Home;
  static const Event End;
  static const Event PageUp;
  static const Event PageDown;

  // --- Function keys ---
  static const Event F1, F2, F3, F4, F5, F6, F7, F8, F9, F10, F11, F12;

  // --- Control keys ---
  static const Event a, A, CtrlA, AltA, CtrlAltA;
  static const Event b, B, CtrlB, AltB, CtrlAltB;
  static const Event c, C, CtrlC, AltC, CtrlAltC;
  static const Event d, D, CtrlD, AltD, CtrlAltD;
  static const Event e, E, CtrlE, AltE, CtrlAltE;
  static const Event f, F, CtrlF, AltF, CtrlAltF;
  static const Event g, G, CtrlG, AltG, CtrlAltG;
  static const Event h, H, CtrlH, AltH, CtrlAltH;
  static const Event i, I, CtrlI, AltI, CtrlAltI;
  static const Event j, J, CtrlJ, AltJ, CtrlAltJ;
  static const Event k, K, CtrlK, AltK, CtrlAltK;
  static const Event l, L, CtrlL, AltL, CtrlAltL;
  static const Event m, M, CtrlM, AltM, CtrlAltM;
  static const Event n, N, CtrlN, AltN, CtrlAltN;
  static const Event o, O, CtrlO, AltO, CtrlAltO;
  static const Event p, P, CtrlP, AltP, CtrlAltP;
  static const Event q, Q, CtrlQ, AltQ, CtrlAltQ;
  static const Event r, R, CtrlR, AltR, CtrlAltR;
  static const Event s, S, CtrlS, AltS, CtrlAltS;
  static const Event t, T, CtrlT, AltT, CtrlAltT;
  static const Event u, U, CtrlU, AltU, CtrlAltU;
  static const Event v, V, CtrlV, AltV, CtrlAltV;
  static const Event w, W, CtrlW, AltW, CtrlAltW;
  static const Event x, X, CtrlX, AltX, CtrlAltX;
  static const Event y, Y, CtrlY, AltY, CtrlAltY;
  static const Event z, Z, CtrlZ, AltZ, CtrlAltZ;

  ...
  
};