TrainCarts/Signs/Statements
Introduction
The switcher, detector and skip signs use statements to conditionally switch track, toggle levers or perform other kinds of actions. Typically the third and fourth lines of signs are used to put these statements. You can also typically add additional signs below the sign to expand the number of statements indefinitely.
Use cases
For routing trains around your Minecraft world, the path finding feature is more than adequate. If you need to categorize carts based on certain attributes and then conditionally activate certain signs or send the train a certain way, then statements cover that gap. A few examples where this can be used.
Remove empty minecarts
If the minecart contains no passenger, a destructor sign is powered.
Send the train once it contains items
Once the train contains an item, power a station sign.
Send a train to a certain player
If the cart is owned by a set player, the track is toggled to lead to that player.
Syntax
You can put a !-sign in front of the statement to act as a NOT. You can read 'the train' as 'the cart' if [cart] is used on the first line. Statements with the format name@<array> are called array statements and can operate on multiple of a certain property. For example, i@wood operates on the items in the train, and checks if there is wood in there. For multiple items, delimit using a semicolon ( ; ), for example ed@north;south will match trains moving towards north or south only.
Most statements also support operators. Operators are:
- = equals
- != not equals
- >= greater or equal than
- <= smaller or equal than
- > greater than
- < smaller than
To use an operator, append it after the statement. For example, minecarts>=5 will check if there are more than 5 minecarts in the train. trainsize>=5 also counts storage and powered minecarts. You can even use it in arrays. Using i@stone=64 you can check if there are exactly 64 stone in the train. All statements that can be interpreted as an amount have operator support, including counting the amount of mobs in the train: m@cow>5. If no operator is given the default operator >0 is used, or in the case of items, the amount that is specified in front of the item name.
| Statement | Meaning |
|---|---|
| passenger | The train has a passenger |
| items | The train contains a chest and has items |
| empty | The train has no passenger and no items |
| fuel | The train contains a furnace which has fuel |
| trainsize | The train cart count matches (e.g.: trainsize>=3) |
| chest_minecart | The train has a number of chest minecarts (e.g.: chest_minecart>=1). Also works for hoppers/powered/etc. types. |
| velocity speed |
The train velocity (movement speed) can be evaluated, or gets if the train is moving |
| powered | The train contains a powered minecart |
| storage | The train contains a storage minecart |
| minecart | The train contains a regular minecart |
| redstone | The sign is powered by redstone |
| maxspeed | Evaluate the maximum speed set |
| mobenter | Checks the mob enter property |
| playerenter | Checks the player enter property |
| playerexit | Checks the player exit property |
| destination | Checks if a destination is set on the train |
| random | Has a 50% chance of turning on |
| n@<names> name@<names> |
The train name equals one of the names specified |
| i@<items> | The train contains one of the items specified |
| o@<owner> | The train contains this owner |
| d@<destination> | One cart in the train has this destination set |
| p@<player> | The train is occupied by this player |
| m@<mobnames> | The train is occupied by one of these mobs |
| pi@<items> | One of the players has one of the items in his inventory |
| ph@<items> | One of the players has one of the items in his hand |
| ed@<directions> | The minecart is moving into a given direction (switcher: upon entering the sign) |
| rs@<directions> | The sign is powered from one of the directions specified |
| [email protected] | Has a 30% chance of turning on (instead of the default 50%) (1.0 is equivalent to 100%) |
| anything t@<tags> |
For anything else the plugin checks if the train has it set as a tag |
And logic
Since everything is evaluated as an OR, how can you check if the train has two of the same? The easiest method is to invert two statements, toggling a lever which powers an inverted sign. For example:
 [cart] switcher !o@me !a |
[!cart] chest in |
| If not owned by 'me' or not has tag 'a' then not transfer items | |
| If owned by 'me' and has tag 'a' transfer items | |
If this proves too hard to do (you need to evaluate more than 3 statements), you will have to use a redstone circuit and multiple switcher signs instead.
Tags
For all statements other than in the syntax table above, the name is compared to tags on the train. To find the tags, you can use wildcards to check for multiple tags at once:
* - has a tag !* - has no tags *a - has a tag ending with 'a' a* - has a tag starting with 'a' *a* - has a tag containing 'a' *ab*cd* - has a tag containing both 'ab' and 'cd'
For example, the following sign uses tags to switch tracks. If the train contains a tag starting with station it goes left, if it contains a tag containing main it will go right. If it contains both, it will go straight ahead.