Tag Archives: Domain

Dark side of programming, hard coding, it’s more code now than game

The definition of a DSL, the applicability of DSLs to AI in particular, the practical side of constructing and deploying DSLs for AI, and the benefits (and beneficiaries) of DSLs for AI. Lastly, we will conclude with some advice from hard experience on the subject.

A Domain-Specific Language is mere a language designed to be highly adept at solving a specific class of problems. Some languages are more specialized than others, some languages are designed to execute in certain environments and some languages are intended to be as widely applicable as possible

The first major principle that motivates our application of DSLs is code cleanliness and the effects of mapping code directly into the problem space (versus code which is too generalized, too abstract, or too specific – i.e. “hard coded”). The second major principle that motivates DSL deployment is elimination of irrelevant concerns. Our third motivating principle: removing excess overhead.

Scripts were developed in the early AI work by Roger Schank, Robert P. Abelson and their research group as a method of representing procedural knowledge. They are very much like frames, only the values that fill the slots must be ordered. A script is a structured representation describing a stereotyped sequence of events in a particular context. Scripts are used in natural language understanding systems to organize a knowledge base in terms of the situations that the system should understand.

The classic example of a script involves the typical sequence of events that occur when a person drinks in a restaurant: finding a seat, reading the menu, ordering drinks from the waitstaff. In the script form, these would be decomposed into conceptual transitions, such as MTRANS and PTRANS, which refer to mental transitions [of information] and physical transitions.

Schank, Abelson and their colleagues tackled some of the most difficult problems in artificial intelligence (i.e., story understanding), but ultimately their line of work ended without tangible success. This type of work received little attention after the 1980s, but it is very influential in later knowledge representation techniques, such as case-based reasoning.

Scripts can be inflexible. To deal with inflexibility, smaller modules called memory organization packets (MOP) can be combined in a way that is appropriate for the situation. The behavior design is the roadmap for our AI scripting, giving us a clear set of coding elements to complete before it’s AI takes shape.

Although there are many different methods of designing AI, including sophisticated methods such as neural networks and artificial evolution, with a simple creature like this, our tutorial will follow the most basic and standard method used by all stock Unreal AI; conditional decision-making. This is the method that takes stimuli as a constant condition or trigger to either do this or that; also known as “if this, then do that”, or “if-then” decision-making. A common example of this kind of AI is the AI Script in a Scripted Sequence, but even Bots use this method, just in an extremely complex form.

We have some features of our NPC already defined for us; its model, textures, animation and sounds. Normally, a custom character would be started by defining its purpose or goal and then design those features around it. But for this behavior design, we will work “backwards”; starting with those features and finding the purpose and behavior design that fits it.

These are misconceptions about DSL development. DSLs are, by definition, simple and to the point. They eliminate the bulk of the issues that plague generic languages and require far less infrastructure to deploy effectively. Additionally, they require much less up-front design and development work.

Programmers in general are lazy and often try to find the simplest approach. This is isn’t necessarily a vice, after all, technology is a means to maximize efficiency by decreasing the energy and time required to do something. This is a god send for game developers as better technology can enable them to produce the best software and interface possible in shorter time spans given how higher ups give them specific deadlines. Scripts are ideal because of their flexibility, that way programmers can make necessary changes in time, with hard code it would be near impossible.

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