Scriptblocks

A rmod fork that removes everything except scriptblocks, and adds to scriptblocks and makes them more efficient.

rmod compatibility

The scriptblocks mod aims to keep backwards compatibility with rmod, so servers that used to use or are even still using rmod will face no issues when changing to scriptblocks. However, moving back from scriptblocks to rmod will void all existing scriptblocks. Any complex scriptblocks machine (over 30 nodes long) will be "cut off" by the new anti-denial-of-service system.

Known issues when "upgrading" from rmod

• Variables in scripts will be lost. Currently, the only way to avoid this is to keep using rmod's scriptblocks until this bug is fixed.

What are scriptblocks?

Scriptblocks are blocks that you can use for creating simple programs. They are one of the most complicated parts of rmod, which can be a good thing or a bad thing depending on your viewpoint.

An important note

Scriptblocks can handle values of various types, such as objects (tables), strings, numbers and booleans. Recent changes mean that scriptblocks no longer convert between them when it is unnecessary. As a result, attempting to compare the equality of, say, a boolean with the string "true" will result in false, because a boolean is not a string. Please keep this in mind as you program with scriptblocks, to avoid messy coding (or building) and frustration.

Any scriptblocks script over 30 nodes long will be "cut off" to prevent infinite loops and fork bombs. If you take advantage of this feature in this code, please note that this restriction is arbitrary and may be changed at any time.

How to use scriptblocks

Basics

When the Mesecon Receiver scriptblock (which is yellow with an exclamation mark on it) receives mesecon power, it triggers any scriptblocks adjacent to it. Each scriptblock will then trigger each scriptblock adjacent to itself (excluding the one that triggered it in the first place).

Variables

You can store data in these scripts with the SET (looks like :=) and GET (looks like []) blocks. Each script can keep track of up to two values during execution (@info and @last), and the GET block will update @last to the previous @info, while updating @info to the value of the chosen variable. All scriptblock inputs may have @info or @last written inside them, which will be substituted for the corresponding values at runtime.

When data is pushed to @info, @last is updated to the previous @info. In this manner, the system is like a stack with extremely low memory - it will only store the two most recent items of the stack.

Program channels

Program channels are channels you can set to share and/or avoid clashing with other programs that may use similar or equal variable names. You can still set the variables of other channels by entering them into SET and GET variable blocks.

Channel names can be protected the same way pipeworks teleportation tubes can. The channel player:test can only be accessed by player, however player;test can be read by anyone but only written to by player.

If the program channel is unspecified, it will be set to the channel in the mesecons/digilines receiver, and if that is empty, to a protected channel owned by the server containing the co-ordinates.

Mathematical operations

The mathematical operations (add, subtract, multiply, divide) work in much the same way as GET - they update @last to the previous @info, and update @info to the result of the calculation. To add two values together, you would do (or rather, build) something along the lines of GET a; GET b; ADD @last @info; SET c @info;, which will set c to the sum of a and b.

Booleans

There are comparison operators which will return true or false depending on whether their condition is true. For example, a "LESS THAN" block with A = 3 and B = 2 will return false, while one with A = 1 instead will return true. Booleans themselves can be manipulated with NOT (turns false into true and vice versa), AND (only true if both operands are true) and OR (only false if both operands are false).

Note that in the case of AND and OR, the two operands are taken to be @info and @last respectively, since they are expected to be booleans - and being able to input true or false directly into one doesn't make sense (what's the point of true OR x or false AND y?).

Conditional

The teal "?" block will lend execution towards the green side if the value reaching it (@info) is non-nil, and non-false. If it /is/ nil or false, execution is lent towards the red side instead. Formerly this took two operands and compared them, but that functionality has been replaced by the comparison operators described above.

Print

The purple blocks with a speech bubble on them will print the message specified inside to the chat. If the player name is left empty, the message is sent to everyone - otherwise, it is sent to that player.

Guide

The grey blocks which look like three arrows that converge into one are guides - they are used to aid looping by funnelling all execution in one direction - never will a guide execute nearby blocks other than the one it is pointing to.

Player Detector

The blue block with the simplified logo of a player avatar is the Player Detector. When it is run, it updates @last to the previous @info and updates @info to the name of the nearest player.

Objects

The bright cyan blocks (GET ATTRIBUTE OF OBJECT, SET ATTRIBUTE OF OBJECT, and NEW OBJECT) can be used to create complex objects, modify and get their attributes.

Digiline Receiver

These are pastel blue equivalents to the Mesecon Detectors, and will trigger adjacent scriptblocks when a digiline message with the specified digiline channel is received. The information contained in the message is stored in @info, so that you can store it in a program variable. If the information is in the form of a table, you can modify it with the object blocks described earlier.

Digiline Sender

These are the polar opposites of the Digiline Receivers - they will send the data contained in @info on the specified channel.

Mesecon Sender

Similar to digiline senders, these scriptblocks send out a mesecon signal. They can be configured in multiple ways, including:

• 0.1 to 5: Pulse mode, where the scriptblock send an 'on' signal for a predefined amount of time before sending an 'off' signal.
• 0: Toggle mode, where the scriptblock will toggle on and off.
• @info, @last: Evaluate either @info or @last and turn on or off accordingly. If the value is a number, it will switch to pulse mode and use the time specified as the delay.

Type blocks

The type blocks deal with the basic types of the system - strings, numbers, booleans, and tables (called objects in this mod). You can use the GET TYPE block to get the type of the current @info, and you can use the NUMBER LITERAL and STRING LITERAL blocks to set @info to a set value (even the string "@info" itself - the automatic substitution system isn't applied here).