aa24cb41fd
Mass changes: • Make the queue handler only run when required and with a delay of `tick_delay`. • Launch the queue handler if it is not running and a queue item is added. • Add `scriptblocks.create_formspec_handler()` to shrink code size by de-duplicating code. • Add pipeworks-style protected program namespaces. |
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| textures | ||
| LICENSE.md | ||
| README.md | ||
| core.lua | ||
| depends.txt | ||
| digilines.lua | ||
| init.lua | ||
| mesecons.lua | ||
| scriptblock.lua | ||
README.md
Scriptblocks
A RMod fork that adds scriptblocks, allowing users to easily create programs and send variables over long distances.
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.
Original description
Scriptblocks are blocks that you can use for creating simple programs. They are one of the most complicated parts of this mod, 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 (building? :P) and frustration.
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 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.
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 to me (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.
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 ran, 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.
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).