toggleF :: Bool -> [(ModState, KeySym)] -> F a b -> F (Either Bool a) (Either Bool b)
toggleF inside keys lblF
toggleF creates a toggle button. An argument fudgets determines the
label placed to the right of the button.
Left on switches on or off the button. Right x
passes x to the label fudget.
Left on when the button is toggled. Right y when the
label fudget outputs y.
inside :: BoolTrue to put the label inside the button.
keys :: [(ModState, KeySym)]lblF :: F a b
toggleF False [] nullF
