This essay, "Rule-Based Programming in Interactive Fiction," by Emily Short, delves into the potential benefits and implementation strategies of using a rule-based approach for designing interactive fiction (IF). Rather than relying solely on procedural or object-oriented programming paradigms typically found in IF development systems like Inform, Short advocates for exploring rule-based systems as a more natural and expressive way to represent the intricate logic and dynamic responses required for compelling interactive narratives.
The core concept of rule-based programming, as explained in the essay, involves defining a set of "rules" that dictate how the game world reacts to player actions and other events. These rules, often expressed in a format reminiscent of logical implications (if this condition is met, then this action occurs), encapsulate the cause-and-effect relationships that govern the game's behavior. This approach allows for a more declarative style of programming, focusing on describing what should happen under specific circumstances, rather than meticulously outlining how to achieve those outcomes procedurally.
Short illustrates the advantages of rule-based systems by highlighting their ability to handle complex interactions and dependencies with greater elegance and maintainability. She argues that traditional procedural approaches can become unwieldy when dealing with numerous interconnected objects and events, leading to tangled code and difficulty in predicting the consequences of player choices. In contrast, a well-defined set of rules can offer a more transparent and modular structure, making it easier to understand, modify, and debug the game's logic.
The essay also explores different methods for implementing rule-based systems in IF, including the use of specialized rule engines or the adaptation of existing IF development tools. It discusses the concept of "pattern matching," where rules are triggered based on matching specific patterns of events or conditions within the game world. Furthermore, it touches upon the importance of conflict resolution strategies when multiple rules are applicable in a given situation, suggesting methods such as rule prioritization or specialized conflict resolution mechanisms to ensure consistent and predictable behavior.
Short acknowledges that rule-based programming may not be a universal solution for all IF development scenarios. She notes that certain types of games, particularly those heavily reliant on complex simulations or intricate algorithms, might be better served by traditional procedural or object-oriented approaches. However, she emphasizes the significant potential of rule-based systems to streamline the development process and enhance the expressiveness of interactive narratives, particularly in games that emphasize complex character interactions, dynamic world states, and intricate plot developments. By abstracting away low-level implementation details and focusing on the high-level logic of the game world, rule-based programming, she argues, empowers authors to create richer and more responsive interactive experiences.
The blog post "Standard Patterns in Choice-Based Games (2015)" by Emily Short explores common design patterns employed in interactive narratives, specifically those using a choice-based structure where the player progresses the story by selecting from presented options. Short argues that understanding these recurring structures can be beneficial for both authors creating these games and players engaging with them. Recognizing these patterns allows authors to deliberately utilize established techniques, potentially streamlining the development process and creating a more consistent player experience. For players, awareness of these patterns can enhance their understanding of the underlying mechanics driving the narrative, allowing for more strategic engagement with the choices presented.
The post identifies several key patterns, categorizing them for clarity. One prominent category revolves around gating, where access to content or specific outcomes is controlled by earlier choices, often involving acquiring items, skills, or relationships. These gates can function as prerequisites, locking off content until specific criteria are met, or as branching paths, diverting the narrative based on the player's accumulated state. This pattern can enhance replayability by incentivizing players to explore different paths on subsequent playthroughs to unlock previously inaccessible content.
Another significant category encompasses timers and counters. This refers to the implementation of hidden or explicit tracking mechanisms that influence the narrative's progression. A timer might represent a deadline the player must meet, while a counter could track the accumulation of resources or the development of a relationship. These mechanisms introduce a sense of urgency or consequence to player choices, as inaction or specific actions can increment or decrement these values, impacting future events. The post highlights how these mechanics can create a dynamic and evolving narrative landscape, even within the constraints of a choice-based system.
Short also discusses patterns related to character relationships and internal states. These patterns often involve tracking the player character's relationship with non-player characters (NPCs), influencing the availability of certain dialogue options, actions, or even entire plotlines. The internal state of the player character, including traits like personality, morality, or mental health, can also be tracked and influence the unfolding narrative in similar ways. This allows for a more personalized player experience, reflecting the consequences of choices on the player character's development and relationships.
The post further delves into hub and spoke structures, where the narrative revolves around a central location or concept (the hub) from which various self-contained storylines (the spokes) branch out. This allows players to explore different facets of the narrative world at their own pace, returning to the central hub to select new avenues for exploration. This structure offers flexibility in narrative design and can accommodate varying lengths and complexities of individual storylines.
Finally, Short touches upon the concept of nested patterns, where multiple patterns are combined or layered to create more intricate and nuanced narrative experiences. For example, a gated section of the narrative might itself contain timers and counters, adding complexity to the player's decision-making process. This demonstrates the potential for sophisticated and dynamic storytelling even within the seemingly simple framework of choice-based games.
By highlighting these patterns, the blog post provides a valuable framework for understanding the underlying design principles of choice-based games, fostering both greater appreciation for existing games and offering guidance for aspiring creators. It emphasizes that despite the apparent simplicity of choosing between predetermined options, the strategic deployment of these patterns can result in rich, engaging, and replayable interactive narratives.
The Hacker News post titled "Standard patterns in choice-based games (2015)" has generated a moderate number of comments, delving into various aspects of choice-based game design. While not an overwhelming discussion, several commenters offer interesting perspectives.
One compelling thread revolves around the tension between player agency and pre-authored narrative. A commenter argues that choice-based games often create an illusion of choice, where pre-determined outcomes are simply dressed up with different wording. They suggest that true player agency requires more dynamic systems, where choices have meaningful and lasting consequences that ripple through the narrative. This sparks a small debate, with others arguing that the enjoyment of choice-based games lies precisely in experiencing carefully crafted narratives, and that excessive player agency can lead to incoherent or unsatisfying stories. The discussion touches upon the inherent limitations of the format, and the different expectations players might bring to these types of games.
Another commenter highlights the importance of pacing and information control in choice-based games. They argue that effective games carefully reveal information to the player, creating suspense and a sense of discovery. Choices should feel meaningful not just in their immediate consequences, but also in how they shape the player's understanding of the game world and its underlying mysteries. This comment connects to the earlier discussion about player agency, suggesting that a sense of agency can be achieved through strategic information management, even within a pre-authored narrative.
A few commenters also discuss specific examples of choice-based games, both successful and unsuccessful, illustrating the points raised in the broader discussion. These examples range from classic text adventures to more modern visual novels, highlighting the evolution of the genre and the different design approaches employed.
While the discussion isn't exceptionally lengthy, it offers some insightful perspectives on the challenges and opportunities of choice-based game design, touching upon issues of narrative structure, player agency, and information control. The comments generally agree on the importance of carefully crafted narratives, while differing on the degree of player agency that is desirable or even achievable within the format.
Summary of Comments ( 3 )
https://news.ycombinator.com/item?id=42748534
HN users discuss the merits and drawbacks of rule-based programming for interactive fiction, specifically in Inform 7. Some argue that while appearing simpler initially, rule-based systems can become complex and difficult to debug as interactions grow, leading to unpredictable behavior. Others appreciate the declarative nature and find it well-suited for IF's logic, particularly for handling complex scenarios with many objects and states. The potential performance implications of a rule-based engine are also raised. Several commenters express nostalgia for older IF systems and debate the balance between authoring complexity and expressive power offered by different programming paradigms. A recurring theme is the importance of choosing the right tool for the job, acknowledging that rule-based approaches might be ideal for some types of IF but not others. Finally, some users highlight the benefits of declarative programming for expressing relationships and constraints clearly.
The Hacker News post titled "Rule-Based Programming in Interactive Fiction" sparked a discussion with several interesting comments revolving around the use of rule-based systems, specifically in interactive fiction but also touching upon broader programming contexts.
One commenter highlighted the historical context of rule-based systems in AI and expert systems, pointing out their prevalence in the 1980s and their decline due to perceived limitations. They expressed intrigue at the potential resurgence of these systems, particularly in interactive fiction, suggesting that they might be a good fit for the genre. This commenter also questioned whether modern Prolog implementations are significantly improved over older ones, pondering if today's hardware might make them more viable.
Another commenter drew a parallel between rule-based systems and declarative programming, suggesting that the declarative nature simplifies complex logic. They specifically mentioned the advantage of avoiding explicit state management, which is often a source of bugs in traditional imperative programming.
A separate comment chain discussed the potential benefits and drawbacks of using Prolog for game development, with one person mentioning its use in the game "Shenzhen I/O." They praised Prolog's suitability for puzzle games where logic is paramount but also acknowledged the steep learning curve associated with the language. This spurred a brief discussion about the challenges of debugging Prolog code, with some suggesting that its declarative nature can make it harder to trace the flow of execution.
One commenter suggested that while Prolog and similar logic programming languages might not be ideal for performance-intensive tasks, they excel in scenarios involving complex rules and constraints, such as legal or financial systems. They posited that in such domains, the clarity and expressiveness of rule-based systems outweigh performance concerns.
Another commenter focused on the practical aspects of incorporating rule-based systems into existing game engines, specifically mentioning the possibility of using a rule engine as a scripting language within a larger game framework. They also touched on the potential for using such systems to implement dialogue trees and other interactive narrative elements.
Finally, some comments simply expressed appreciation for the article and the insights it provided into the history and potential applications of rule-based programming. They acknowledged the challenges of adopting such systems but also recognized their power and elegance in certain contexts.