This will be a quick overview of what I’m calling “response-based” IF, which is what the ResponsIF engine is designed to do. It won’t get too in-depth into the nuances of the engine itself but will strive more to give the overall design considerations.
In general terms, a “response” is a unit of behavior. A response can output text (or other elements), change variables in the world state, move objects around, invoke other responses, etc. or any combination of the above. Anything that occurs in the course of interaction is done through some sort of response.
Responses are triggered by “topics”. A topic is anything you can think of. Nouns, verbs, ideas, emotions, pretty much anything you can think of can be a topic. If you can express it, then it can be a topic. A topic is “called” to generate responses.
Responses do not exist on their own. Rather, responses are provided by “responders”. A responder provides one type of context for when a response can be triggered – a response can only trigger when its responder is part of the active scene. (There are other sorts of context for responses as well, including the topic(s) to match and any necessary world state conditions.)
Let’s give a simple example of a response: the ubiquitous “Hello world” response.
.responses player .response START .does .says Hello, world! .end
The key elements are here. The first line (“.responses player”) states that we are defining the responses for the “player” responder. The “player” responder is the only built-in responder in ResponsIF, and it is active in any response context. It is meant to correspond to the person playing (or reading or whatever) the current IF piece.
The next line (“.response START”) begins a definition for a response, responding to the topic “START”. The “START” topic is called by default when a ResponsIF piece begins.
The subsequent line defines what the response does: it outputs the string “Hello, world!”
Finally, “.end” terminates the set of responses for the player.
This is just a single response, and it doesn’t do much. But it should give an idea about how a ResponsIF game or work (termed a “riff”) is structured. An entire riff contains statements to set up the game world along with a collection of responders and their responses which will occur when various topics are called. Responders can be arranged in a hierarchical structure (parent/child) to establish the necessary contexts or even model “world” structures like rooms, hallways, caverns, etc.
How are topics called? Sometimes they’re called internally, as the “START” example shows. They can also be called by other responses. The vast majority of topics will be called due to player action, typically through UI elements such as buttons, hyper-links and textual input.
For example, the following rather pointless example shows how hyper-links can be created to call topics.
.responses player
.response START
.does .says Once upon a time, there was a {!princess!} who lived in a tall {!tower!}.
.response princess
.does .says She had long luxurious hair.
.response tower
.does .says The tower had smooth, stone walls that not even ivy could scale.
.end
The notation “{!princess!}” is called “link markup”. It creates a link that will call the specified topic (“princess”) when clicked.
The exact ResponsIF details are not terribly relevant here, beyond showing the basic concepts. (More details can be found at the ResponsIF github site: https://github.com/jaynabonne/responsif.)
A key part of ResponsIF is its use of HTML, CSS and JavaScript, which provides great freedom in how a work looks and feels. Due to this, ResponsIF can be used to create a large number of possible works. As a general-purpose engine, it is not restricted to any particular form of IF. Of course, being a general-purpose engine, it’s also not specialized for any particular form of IF, which means it may make more sense to use other tools more dedicated to a particular form, depending on what end result is desired. As always, choose the tool that best matches the task at hand!
In upcoming posts, I will go over my own personal goals and design choices for my IF work(s).