w_to

w_to is a direction property given to rooms. When a player types, “GO WEST”, DoGo checks that value to see if there is another room in that direction.

room twistypassage "A Maze of Twisty Passage"
{
    long_desc
        "You are in a maze of twisty passage. There is one exit to the west."
    w_to twistypassage2
}

It is aliased by the contains_desc property.