Scripts!

So what is a scripting language? and how is it different than a programming language? Do NOT try to find a definitive answer to the second question on a forum! Especially if you're not really a programmer. I tried, it was like a firestorm of confusion in there. Basically, what you need to know is that a scripting language IS a programming language that allows the user the ability to customize the way a specific software application (a game) behaves. It is a high-level language (meaning that it is closer to human language rather than computer language) which is easy for both programmer and none-programmers to use and allow them access to most of the commonly used functions of the engine. Scripting allows these users to do anything from modding a current game to make a completely new game. Though do not think that scripting languages simply come on in one flavour, there are several different kinds of scripting languages that may have different functions or may focus on different characteristics.

One such distinction between languages is whether or not the language is interpreted or compiled. Compiled languages use a program called a compiler to transform or translate the script into machine code which can then be used by the CPU (though scripting languages are not compiled but instead interpreted as you will read later). Interpreted languages on the other hand can be parsed directly at runtime or it can be precompiled into byte code which is then processed by a virtual machine which is essentially a CPU but not really... it's like it exists but doesn't REALLY exist... it's like a holographic CPU O.K? Regardless, virtual machines can be put on almost machine but the downside is that they are slower than a real REAL CPU...sigh.

Moving on we come to functional languages where distinguishes its self from the other kinds of languages in that programs are defined by a collection of functions. They take in input data and run them through the functions one after the other until the desired output occurs.

Then there are procedural and object-oriented languages, where object-oriented languages focus on classes (structures that use functions to manage data) procedural languages focus on functions themselves to manage data as oppose to using classes which use functions.

These languages can also differ in whether they used a text based language such as LUA or a graphical based language like Unreal's Kismet. I am very interested in the kismet mainly because of the number of features focused on improving the user's workflow such as allowing the user to make changes to the script and see immediately the changes made while game is running.

This next video provides a more in depth look at what you can do with the kismet and what the Unreal Engine 4 is capable of (sadly, I dont think our school laptops are capable of providing that level of graphical fidelity without exploding).

Though regardless of the "flavour" of language you prefer, there are certain characteristics that all scripting languages share. Such that all scripting languages are interpreted as opposed to being compiled because this allows the scripting languages to be highly flexible and easily transferable because, as mentioned before they can be converted into byte code which can easily be put into memory instead of requiring the operating system as with compiled languages. Virtual machines also grant scripts a large amount flexibility regard when code is run because, as mentioned before, they are CPUs... but not really.

Scripting languages also tend to be rather simple and use very little memory because they have to be able to be put inside or embedded into a preexisting system. They are like a reverse tumour where you them in as oppose to taking them out and they are good for the system as oppose to bad, which is good...I think.

Another characteristic of scripting languages is that any changes you make to the code you have made do not require you to exit the game (if it is running), make your changes to the code, and then recompile the entire thing as with compiled languages. Though some scripting languages may require you to exit the game they do not require recompilation and some languages allow the scripts to be changing while the game is running like Unreal's Kismet. Though regardless of whether or not the language requires you to exit the game or not, they are all allow users to make changes to the code a lot faster than compiled languages.

Scripting languages are also easy to use and convenient, which is reflected by their simplicity. This is because scripting languages are used by programmers and none-programmers alike, specifically designers. So the scripting language must provide feature specific to the game the designer is creating such as the ability to pause and manipulate time, and finding game objects by name. This allows the designer and any other person using it to easily understand the language and make the necessary changes.

Scripts, as mentioned by Isla, act as a sort of "glue" or mortar between the components of code,  creating a sort of stone wall where the stone themselves (components) aim to be reusable for other walls (games), the scripts are specific to that wall.

But when it comes to writing a scripting language one must remember the characteristics of the scripting languages as mentioned above in that they must be flexible, easy to use, and they do not require compilation. Of course, writing ones own scripting language is not recommended especially if you have other important things to do. I hope the lead programmer of my game dev group does not read this cause I'm sure he would be all:

In which case I would promptly find a bridge to jump off of, preferably one with deep enough waters underneath that I could easily fake my own death and move to some far off country under the name of Pablo Escobar.

(facepalm* I googled that name and found out he was a big Colombian drug lord. Yup! Perfectly inconspicuous! That name won't get you selected for a "random" search by airport security at all!)

Despite all the difference mentioned before, the use of scripting languages are used to give more power to the designers and other non-programmers which is where scripts can do the most good because they allow the designer or artist or whomever to make easy, quick changes the the game so as to better bring out their vision of what the game should be.

sources

http://www.youtube.com/watch?v=IReehyN6iCc

http://www.youtube.com/watch?v=VitLyrynBgU

Gregory, Jason.Game Engine Architecture. Boca Raton: CRC Press, 2009.

Lewis, Mike."Flirting with The Dark Side: Domain Specific Languages and AI". File last modified 14 Nov.2013. Microsoft PowerPoint file.

Isla, Damian. "Scripting and AI: Flirting with The Dark Side". File last modified 16 Nov. 2013. Microsoft PowerPoint file.

http://images.wikia.com/animalcrossing/images/0/08/Challenge_accepted.png

http://collider.com/wp-content/uploads/pablo-escobar.jpg