CUSTOM-CALL-STACK.md

Overwatch Workshop: Custom Call Stack

Table of Contents

• Background
• Implementation
• Usage

Background

Implementation

Usage

Declare variable:

// let variable1 = 0;
Global.Stack1[Global.Stack1[1]] = Custom String("variable1");
Global.Stack1[Global.Stack1[1] + 1] = 0;
Global.Stack1[1] += 2;

Accessing Variable Value in Scope:

// variable1
Global.Stack[Index Of Array Value(Array Slice(Global.Stack, Global.Stack[0], Global.Stack[1] - Global.Stack[0]), Custom String("variable1")) + 1 + Global.Stack[0]]

Accessing Global Variable Value:

// variable1
Global.Stack[Index Of Array Value(Global.Stack, Custom String("variable1")) + 1]

For loop:

// let i = 0;
Global.Stack[Global.Stack[1]] = Custom String("i");
Global.Stack[Global.Stack[1] + 1] = 0;
Global.Stack[1] += 2;

// while (i < 5)
While(Global.Stack1[Index Of Array Value(Array Slice(Global.Stack1, Global.Stack1[0], Global.Stack1[1] - Global.Stack1[0]), Custom String("i")) + 1 + Global.Stack1[0]] < 5);
	...
	// i += 1;
	Global.Stack1[Index Of Array Value(Array Slice(Global.Stack1, Global.Stack1[0], Global.Stack1[1] - Global.Stack1[0]), Custom String("i")) + 1 + Global.Stack1[0]] += 1;
End;

Calling subroutines as functions with no parameters:

rule("Previous Action")
{
	...

	actions
	{
		...

		// Return Address
		Global.Stack1[Global.Stack1[1]] = Global.Stack1[0];
		Global.Stack1[1] += 1;

		// SubroutineName();
		Call Subroutine(SubroutineName);

		...
	}
}

rule("Called Subroutine")
{
	event
	{
		Subroutine;
		SubroutineName;
	}

	...

	actions
	{
		// Sets Local Scope (FramePointer) with 0 Parameters
		Global.Stack1[0] = Global.Stack1[1];

		...

		// Rollback stack pointer
		Global.Stack1[1] = Global.Stack1[0] - 1;
		// Set scope to previous (FramePointer)
		Global.Stack1[0] = Global.Stack1[Global.Stack1[1]];
	}
}

Calling subroutines as functions with parameters:

rule("Previous Action")
{
	...

	actions
	{
		...

		// Return Address
		Global.Stack1[Global.Stack1[1]] = Global.Stack1[0];
		Global.Stack1[1] += 1;

		// parameter: parameter1 = 0;
		Global.Stack1[Global.Stack1[1]] = Custom String("parameter1");
		Global.Stack1[Global.Stack1[1] + 1] = 0;
		Global.Stack1[1] += 2;

		// parameter: parameter2 = 0;
		Global.Stack1[Global.Stack1[1]] = Custom String("parameter2");
		Global.Stack1[Global.Stack1[1] + 1] = 0;
		Global.Stack1[1] += 2;

		// parameter: parameter3 = 0;
		Global.Stack1[Global.Stack1[1]] = Custom String("parameter3");
		Global.Stack1[Global.Stack1[1] + 1] = 0;
		Global.Stack1[1] += 2;

		// SubroutineName(parameter1, parameter2, parameter3);
		Call Subroutine(SubroutineName);

		...
	}
}

rule("Called Subroutine")
{
	event
	{
		Subroutine;
		SubroutineName;
	}

	...

	actions
	{
		// Sets Local Scope (FramePointer) with 3 Parameters
		Global.Stack1[0] = Global.Stack1[1] - (3 * 2);
		
		...

		// Rollback stack pointer
		Global.Stack1[1] = Global.Stack1[0] - 1;
		// Set scope to previous (FramePointer)
		Global.Stack1[0] = Global.Stack1[Global.Stack1[1]];
	}
}