 
 : forward-vector ( player -- v )
     yaw>> 0.0
-    { 0.0 0.0 $ MOVEMENT-SPEED } vneg eye-rotate ;
+    ${ 0.0 0.0 MOVEMENT-SPEED } vneg eye-rotate ;
 : rightward-vector ( player -- v )
     yaw>> 0.0
-    { $ MOVEMENT-SPEED 0.0 0.0 } eye-rotate ;
+    ${ MOVEMENT-SPEED 0.0 0.0 } eye-rotate ;
+: clamp-pitch ( pitch -- pitch' )
+    90.0 min -90.0 max ;
+
 
 : walk-forward ( player -- )
     dup forward-vector [ v+ ] curry change-velocity drop ;

    key-s keys nth [ player walk-backward ] when 
    key-a keys nth [ player walk-leftward ] when 
    key-d keys nth [ player walk-rightward ] when 
    key-space keys nth [ player jump ] when 
    key-escape keys nth [ world close-window ] when
    player read-mouse rotate-with-mouse

: walk-rightward ( player -- )
    dup rightward-vector [ v+ ] curry change-velocity drop ;
: jump ( player -- )
    [ ${ 0.0 JUMP 0.0 } v+ ] change-velocity drop ;
: rotate-leftward ( player x -- )
    [ - ] curry change-yaw drop ;
: rotate-rightward ( player x -- )
    [ + ] curry change-yaw drop ;
: look-horizontally ( player x -- )
    [ + ] curry change-yaw drop ;
: look-vertically ( player x -- )
    [ - clamp-pitch ] curry change-pitch drop ;


: rotate-with-mouse ( player mouse -- )
    [ dx>> MOUSE-SCALE * look-horizontally ]
    [ dy>> MOUSE-SCALE * look-vertically ] 2bi ;

:: handle-input ( world -- )
    world player>> :> player
