Krate Tutorial

Krate

Krate is a 5 bit virtual machine implemented as a configuration file, using scalu. The advantage of this approach is that its incredibly easy to make use of; simply load the VM config in-game, and you're ready to go, no other installations or knowledge necessary.

Registers

Like many VM's, Krate has a collection of registers where it stores values; these registers are simply labeled a,b,c...though z. Each of these registers are 5 bits in size, meaning they can store integers between 0 and 31 inclusive.

You can also simply refer to constants literally. $13, internally, refers to a read-only register with a value of 13.

Sequences

You can interact with Krate through a simple assembly language. There are just two kinds of sequences in this language:

Assignment:

reg1;reg2;reg_output;operator

Conditional:

reg1;reg2;operator

Assignment Sequences

Suppose I want to calculate 7 + 4 and store the result in a register called z, then print that variable to the command line. This is simple:

$7;$4;z;add;print

This will print 11 to the console.

A unary operation:

unary;$7;z;copy

The unary command tells krate to skip processing the first argument.

All assignment operators:

Unary:

copy
not

Binary:

add
sub
or
and

While useful, these commands don't really affect the "outside" world, they only affect the state inside the Krate VM. You can, however, affect the outside world with conditional sequences.

Conditional Sequences

Suppose I want to call my_alias if a is 3, otherwise call my_other_alias.

alias true "my_alias"
alias false "my_other_alias"
a;$3;eq

This will execute "true" and thus "my_alias" if a is 3, otherwise execute "false" and "my_other_alias". "my_alias" and "my_other_alias" are conventional aliases that can be defined however you like.

All conditional operators:

eq - Equals
ne - Not Equals
gt - Greater Than
lt - Less Than
gte - Greater Than or Equal
lte - Less Than or Equal

Composition

The great thing about Krate is that it naturally composes with the native configuration language. Suppose register b represents my current class, for instance. This can be aliased just how you imagine it would be.

Say we want to store the current class in register b:

alias current_class b

alias set_pyro_class "unary;$3;current_class;copy"

This can be further improved; aliasing a constant is sort of like declaring an enum, like in regular programming!

alias pyro_class $3

alias set_pyro_class "unary;pyro_class;current_class;copy"

Jumps

The z register in Krate has a special command called jump; this command acts as a fast way of mapping a number to an action without using a lot of if statements. This is how the print command is implemented! Printing isn't a special part of Krate, anyone can easily recreate it.

alias print "alias jump0 echo 0;alias jump1 echo 1;alias jump2 echo 2;alias jump3 echo 3;alias jump4 echo 4;alias jump5 echo 5;alias jump6 echo 6;alias jump7 echo 7;alias jump8 echo 8;alias jump9 echo 9;alias jump10 echo 10;alias jump11 echo 11;alias jump12 echo 12;alias jump13 echo 13;alias jump14 echo 14;alias jump15 echo 15;alias jump16 echo 16;alias jump17 echo 17;alias jump18 echo 18;alias jump19 echo 19;alias jump20 echo 20;alias jump21 echo 21;alias jump22 echo 22;alias jump23 echo 23;%5du"

alias %5du "alias jump24 echo 24;alias jump25 echo 25;alias jump26 echo 26;alias jump27 echo 27;alias jump28 echo 28;alias jump29 echo 29;alias jump30 echo 30;alias jump31 echo 31;jump"

As you can see, the print statement exhaustively goes through and assigns every jump possibility to echo a certain number.

Building (for developers)

krate.py is a python script which generates a scalu script which generates the output config; Python is only involved because scalu does not have a macro system or compile-time facilities to generate all the boilerplate needed to make compiling krate independently viable. After generation, you'll need to remove event prefixes added by scalu to avoid namespace collision (replace '$' with ''). You will also need to delete all instances of the string "delete"; this is because scalu does not allow naming an event with a number as the first character, so getting around this requires prefixing events with a string of letter characters you delete later (replace 'delete' with '').