dust/examples/clue_solver.ds

all_cards = {
	rooms = ['Library' 'Kitchen' 'Conservatory']
	suspects = ['White' 'Green' 'Scarlett']
	weapons = ['Rope' 'Lead_Pipe' 'Knife']
}

is_ready_to_solve = (fn cards <map>) <bool> {
	((length cards:suspects) == 1)
	&& ((length cards:rooms) == 1)
	&& ((length cards:weapons) == 1)
}

take_turn = (fn cards <map>, opponent_card <str>, current_room <str>) <map> {
	cards = (remove_card cards opponent_card)
	cards = (make_guess cards current_room)
	cards
}

remove_card = (fn cards <map>, opponent_card <str>) <map> {
	cards:rooms -= opponent_card
	cards:suspects -= opponent_card
	cards:weapons -= opponent_card
	cards
}

make_guess = (fn cards <map>, current_room <str>) <map> {
	if (is_ready_to_solve cards) {
		(output 'It was '
			+ cards:suspects:0
			+ ' in the ' 
			+ cards:rooms:0  
			+ ' with the ' 
			+ cards:weapons:0 
			+ '!')
	} else {
		(output 'I accuse '
			+ (random cards:suspects)
			+ ' in the '
			+ current_room
			+ ' with the '
			+ (random cards:weapons)
			+ '.')
	}
	cards
}

all_cards
	-> (take_turn 'Rope' 'Kitchen')
    -> (take_turn 'Library' 'Kitchen')
    -> (take_turn 'Conservatory' 'Kitchen')
    -> (take_turn 'White' 'Kitchen')
    -> (take_turn 'Green' 'Kitchen')
    -> (take_turn 'Knife' 'Kitchen')