Enums

[d.healey]

Should I use enums or is it more efficient to use a const var object or reg variable?

[Christoph Hart]

Use const variables in combination with a namespace. Accessing this is as just as fast as using the actual literal value; everthing else comes with a performance penalty

namespace Direction
{
    const var UP = 0;
    const var DOWN = 1;
    const var BOTH = 2;
};

// Usage:
switch(d)
{
   case Direction.UP:

[d.healey]

Yeah I thought there would be a penalty. What about using enums within a namespace? Since we can't nest namespaces.

[Christoph Hart]

If you're already in a namespace, you can just use const variables - a common rule is to write constant values and enums LIKE_THIS so you don't get confused :)

[d.healey]

How does const var Direction = {UP:0, DOWN:1, BOTH:2}; compare for efficiency to using individual const vars?

[Christoph Hart]

You can profile this easily to measure the difference:

const var DirectionSlow = { "UP": 0, "DOWN": 1, "UP_DOWN": 2};

namespace DirectionFast
{
	const var UP = 0;
	const var DOWN = 1;
	const var UP_DOWN = 2;
};


reg i = 0;

Console.print("");
Console.print("Object Access:");

Console.start();

for(i = 0; i < 1000000; i++)
{
	// Use many accesses to diminish the impact of the loop logic
	DirectionSlow.UP_DOWN;
	DirectionSlow.UP;
	DirectionSlow.DOWN;
	DirectionSlow.UP_DOWN;
	DirectionSlow.UP;
	DirectionSlow.DOWN;
	DirectionSlow.UP_DOWN;
	DirectionSlow.UP;
	DirectionSlow.DOWN;
}
		
Console.stop();

Console.print("Namespace Access:");

Console.start();

for(i = 0; i < 1000000; i++)
{
	Direction.UP_DOWN;
	Direction.UP;
	Direction.DOWN;
	Direction.UP_DOWN;
	Direction.UP;
	Direction.DOWN;
	Direction.UP_DOWN;
	Direction.UP;
	Direction.DOWN;
}
	
Console.stop();

On my system it's 540ms vs 387ms. It's not super critical, but if possible I'd recommend using namespaces.

[d.healey]

Thank you