IGB Compiler L2 compiles IGB L2 code into IGB L1 code.

IGB L2 language supports:

• for and while loops (including break; continue;)
• else if statements
• automaticly allocated variables
• arrays
• functions (including returning values and function arguments)
• floating point values up to 3 decimal places (0.001)
• complex expression solving (var d = a*b/c+1; works just fine)
• an built-in easy to draw canvas
• easy keyboard input checking
• multi-file support
• sqrt
• nested for breaks and continues

The language does NOT support:

• objects
• strings, lists, maps, etc.
• file IO
• dynamic variable allocation (more explained here)
• variables in recursion
• switch statements
• dynamic array size (array size has to be known at compile-time)
• there is only one value type (float), so no int casting

The whole IGB language was designed to be executed in Minecraft (MCMPCv7).
You can also run it on your desktop using IGB VM created for easy program testing.

Examples

Tetris

Hello world wrriten in IGB L2

This code displays the string "Hello world!" on the canvas.

$ramcell = 70;
$startLine = 15000;

$import <charlib>;

void main() {
  width = 72;
  height = 21;
  stype = rgb;
  
  drawstring(3, 0, "Hello world!", "big", 0);
}

Line by line explanation

$ramcell = 70;
$startLine = 15000;

What the hell are those $ things?
They are called "compiler variables", and are used by the compiler.
They cannot be accessed in any way in the rest of your code.
You can set them only once.

Here's a list of compiler variables:

• $startline (required) This where your code is meant to be placed.
  Startlines are only allowed to be >= 15000, since charLib is taking all the previous space.
• $ramcell (required) This where all your variables and arrays will start allocating.
  Ramcells are only allowed to be >= 70, since the previous space is occupied by important variables (see a list of them here).
• $lenlimit (optional) Specifies the maxium instruction size your code can be.
  If your code after compilation to IGB L1 is larger than this number, an error is thrown.
• $ramlimit (optional) Same as $lenlimit but for variables/arrays.
• $thread (optional, default=0) It's working but has no use since threads aren't implemented yet (and probably won't be).
  Diffrent temporary cells for variable and if statement solving are chosen for values 0 or 1.

---

Defining variables

It's not in the Hello World, but some things are important to understand.
Here's a simple variable declaration with initial value:

var a = 5;

You don't need to provide a value:

var a;

IMPORTANT! the | | thingy specifies a cell.
a|70| means that a is going is at cell 70

Example:

var a|75| = 5;

However, the code above didn't allocate any memory. Here's how you can allocate it:

var a|!75| = 5;

If you use the ! sign with a value outside of your allocation array (from $ramcell to $ramcell + $ramlimit) the compiler will cry.

The same with arrays.

var[][] arr1 = new var[7][4];
var[][][] arr2|!80| = new var[16][16];

More about variables here.

---

Dependencies

$import <charlib>;

That's not a compiler variable, that's a dependency.
For example, the code above imported library named charLib, which draws chars on the screen.
If you import a file/library, all of it's functions are shared and can be used as if they were in the same file.
Here are some examples:

$import myfile // it's the same as the line below
$import myfile.igb_l2 
$import mydirectory/myfile1
$import /home/krypek/myfile2 // it's the same as the line below
$import /home/krypek/myfile2.igb_l2

---

Functions

void main() {

Defines the main function. There can only be 1 main function in a file, it has to return void and it cannot have any arguments.
To define a function with a return type, replece void with var

var myfuncthatreturns() {

Add arguments to the function:

var myfuncthatreturns(var a) {

You can have multiple functions with the same name with diffrent amount of arguments:

var myfuncthatreturns() {}
var myfuncthatreturns(var a) {}
void myfuncthatreturns(var a, var b) {}

You don't need to type return; at the end of every function, also it the compiler doesn't cry if you don't return any value at all (100% feature).

---

Built-in variables

width = 100;
height = 30;
stype = rgb;

Those are built-in variables. They work like a normal variables.
List of built-in variables:

• width|1| Screen width
• height|2| Screen height
• stype |3| Can be only set to 16c or rgb.
  Setting it will resize on width and height, set it's type based on stype and fill with #FFFFFF.
• keyboard |4| Keyboard input

---

Compiler functions

Compiler functions can have arguments like strings since they are coonverted to instructions at compile-time. (If the variable type is int, only ints can be provided, same with string)
(If the variable type is cell, only variables or integers can be provided, no expressions)

• exit() Jumps to cell -2
• wait(int tick) Waits tick ticks
• screenUpdate() Updates screen properties based on cells 1, 2 and 3
• dlog(var value) Logs value to the terminal/chat
• drawstring(var x, var y, string text, string type, var spacing)
• sqrt(var variable) Returns the square root of variable
• random(int from, int to) Returns a random integer in range of from and to
• pixelcache(var cache) Sets the pixel cache to cache
• pixelcache(var r, var g, var b) Sets the pixel cache to r, g, b
• setpixel(var x, var y) Sets the pixel color at x y to pixel cache.
• getpixel(var x, var y) Returns the 16c pixel type at x y
• getpixel(var x, var y, cell r, cell g, cell b) Saves the rgb value to cells r, g and b at x y

See theirs implementation here.

drawstring()

drawstring(0, 0, "Hello world!", "big", 0);

For this function to work charLib has to be imported.
The first 2 arguments specify the x & y of the text.
Third argument is text, the forth is what type of text is it.
Text types:

• small (plain, size=14)
• smallitalic (italic, size=14)
• big (plain, size=20)
• bigbold (bold, size=20)
• bigitalic (italic, size=20)
• bigbolditalic (bold & italic, size=20)

The fifth argument is the text spacing.  Y o u r  t e x t  c a n  b e  l i k e  t h i s .

That's the hello world!

---

Variable operations and expressions

Here's a list of supported math operations:

• +
• -
• *
• /
• %

Examples:

var a = 2;
var b = 3;

a++; // a is now 3
b--; // b is now 2

a += b; // a is now 5

b = a * b + b / a;
//    10  +  0.4
// b is now 10.4

b -= b % 1; // manual int casting, b is now 10

Arrays

var[][] arr1 = new arr1[6][7];

arr1[6][2] = 4; // Index of of bounds error

var t1 = 7;
arr1[t1][4] = 6; // No error

t1 = arr1[1][2]; // t1 is now 0

var[][] arr2 = new var[t1][4]; // No dynamic size arrays error

Final variables

final var a = 5;

var[] arr = new arr[a]; // No error becouse array size is known at compile-time

var b = a*a/a+a; // b is set to 10; It's only 1 operation, becouse the expression can be solved at compile-time.

If

var a = 5;
var b = 7;

if(a > b) {
  // dead code
} else if(a == b) {
  // dead code
} else {
  // a < b
  // will always execute
}

// 12  < 35
if(a+b < b*a) {}

For and while loops

for(var i=0; i<3; i++) { dlog(i); } // will print out 0, 1, 2

var a = 1;
for(;a<3; a++) { dlog(i); } // will print out 1, 2

for(int i=0;; i++) { dlog(i); } // infinite loop

for(;;) {} // same as while(true)

while(false) { /*dead code*/ }

while(true) { /* infinite loop*/ }

var a = 0;
while(a < 5) {
  a++;
  dlog(a);
} // will print out 1, 2, 3, 4, 5

for(int i=0; i<10; i++) {
  if(i%2==1) { continue; }
  if(i==6) { break; }
  
  dlog(i);
} // will print out 0, 2, 4

IGB L2 exclusive statements

You can break twice in a for loop.

for(int y=0; y<10; y++) {
  for(int x=0; x<10; x++) {
    if(x+y == 15) {
      break 2; // exits both loops
    }
  }
}

break 1 is the same as break.
The same thing with continue.

Break can be used outside of loops.

if(true) {
  break;
  dlog(1); // dead code
}

New statenent: redo

void a() {
  dlog(1);
  
  redo; // jumps to function start
} // will print a lot of 1's; infinite loop

{ redo; } // infinite loop

var a = 5;
if(a == 5) {
  // ...
  redo;
} // will loop as long a == 5; same as while(a==5)

{
  dlog(1);
  { redo 2; }
} // will print a lot of 1's; infinite loop

New statement: raw

raw is used to insert IGB L1 code

raw Init 5.3 70;

Dependencies:

• FreeArgParser-Java
• IGB-Compiler-L1
• Java-Utils

License

Licensed under GNU GPLv3 or later