Checks whether the specified node name is a track and the train can drive on this track type.

Note: this page has been written for Advtrains 2.0.1 TSS and Minetest 5.1.0. Examples and practices described in this page don't take advantage of improvements introduced in later releases.

advtrains.is_track_and_drives_on(nodename, drives_on_p)

This function is used to check whether a certain node is a valid track. In case a train can only drive on certain Tracktypes, can also restrict the valid tracktypes to the ones given.

• nodename (string): the track node name.
• drives_on_p (table): a table containing tracktype names the train can drive on. Defaults to advtrains.all_tracktypes.

True if the specified node name is a track, and the train can drive on this track.

Firstly, this function checks the parameter drives_on_p. If it is nil or empty, the parameter is replaced with advtrains.all_tracktypes. Then, it checks the existence of the specified nodename - if it does not exist, the function returns immediately. The third step is to check that the track group of the node definition is present in the drives_on_p table.
If one of the keys in the table matches the node name, the function returns true. Otherwise it returns false.

advtrains.is_track_and_drives_on("advtrains:dtrack", nil) -- true
advtrains.is_track_and_drives_on("advtrains:dtrack", {}) -- true
advtrains.is_track_and_drives_on("advtrains:dtrack", { nonstandard = true }) -- false
advtrains.is_track_and_drives_on("tracklib:custom", { nonstandard = true }) -- false unless tracklib:custom has been registered with track type "nonstandard"

advtrains/tracks.lua, lines 365 to 384:

is_track_and_drives_on.lua

function advtrains.is_track_and_drives_on(nodename, drives_on_p)
    local drives_on = drives_on_p
    if not drives_on then drives_on = advtrains.all_tracktypes end
    local hasentry = false
    for _,_ in pairs(drives_on) do
        hasentry=true
    end
    if not hasentry then drives_on = advtrains.all_tracktypes end
 
    if not minetest.registered_nodes[nodename] then
        return false
    end
    local nodedef=minetest.registered_nodes[nodename]
    for k,v in pairs(drives_on) do
        if nodedef.groups["advtrains_track_"..k] then
            return true
        end
    end
    return false
end