Javascript (:) colon

Questions & Answers
1

Ok guys, very sorry if this doesn’t fit anywhere but I gotta know.
What the hell does the : do in javascript/unityscript?

For example:

var backDrop:Texture2D; //HERE
var windowPosition:Vector2=Vector2(200,200);
var windowSize:Vector2=Vector2(96.0,96.0); //AND HERE
var itemIconSize:Vector2=Vector2(32.0,32.0); //AND HERE
var updateListDelay=1.0;
var lastUpdate=0.0;//last time we updated the display.
var UpdatedList:Transform[];
var associatedInventory:Inventory; //LASTLY, HERE

And bonus question, how would one translate that into Boo?

2

The : and the thing that follows it enforce a ‘type’ on that variable. Without it, it’s just a generic object. With it, you know that something is really a Texture2D or Vector2 or Transform etc.

3

my kid uses boo when we play peepo, can’t help with that.

In unity’s take on javascript the colon : is used like “new” is used for declaring object types in what the rest of the world call javascript.

Declarations of a data type is rare in javascript and mostly used for array objects (e.g.

var stuff = new Array();

In normal javascript most things are objects including functions. So the use of typing is rare

see how most of the web interprets javascript below…

http://www.w3schools.com/js/js_datatypes.asp

I find it easier not to think of unity javascript as javascript, so I think of it as unityscript.

Even so I like the possibilities of explicit typing in unity’s javascript, it makes the code easier to read IMHO, its quite easy to get yourself in a mess with strings and number data types in javascript “proper”. Very rarely need to debug simple type issues if at all in Unity.