Research Paper: Designing a Syntactically Elegant and Functional Language for a MUD Game

In this paper, we explore the design of a new programming language tailored for MUD (Multi-User Dungeon) games. The goal is to create a language with intuitive syntax and multi-paradigm support, favoring simplicity, expressiveness, and usability in the domain of game logic, character interaction, and world-building. While functional programming constructs will be central to the language, we also aim to introduce multi-paradigm support, blending the best of procedural and object-oriented approaches where necessary.

The focus will be on language constructs that enable fluid expression of game mechanics, NPC interactions, player input processing, and general scripting for world manipulation. This includes syntax for command handling, state updates, and asynchronous actions. The language will avoid directly cloning any existing language, aiming instead to innovate where necessary.

Key Considerations for Language Design in a MUD Game

• Simplicity and Accessibility: The syntax should be easy to grasp and avoid excessive verbosity.
• Expressiveness: Users should be able to write concise yet readable code.
• Flowing Syntax: Language constructs should make code feel natural, like storytelling.
• Functional Core with Multi-Paradigm Features: The language should promote a functional style but allow procedural and object-oriented patterns for tasks where they make sense.
• Integration with MUD Constructs: The language should have built-in support for common MUD actions such as movement, item interactions, and combat.

Syntax Design Principles

1. Command-Based Syntax: Given the nature of a MUD game, the language should support direct, imperative commands that drive player actions. These commands should be easy to write and read:

   • Movement commands like go north, look at sword, or pick up key.
   • Dialogue commands like say "Hello" or whisper to NPC.

2. Readable Flow for NPC Behavior: NPC behaviors are often scripted. The language should allow for elegant flow control over NPC actions and reactions.

3. Natural Pattern Matching: Pattern matching allows flexible handling of various inputs, like different player commands or event outcomes.

4. Lambdas and Higher-Order Functions: Functions should be first-class citizens, allowing for operations like event handling and game state manipulation.

5. Lightweight Syntax for Asynchronous Operations: Game events often happen asynchronously (e.g., delays in combat or movement). There should be simple constructs for these.

Syntax Constructs

1. Command-Based Constructs

Commands should have a simple syntax that mirrors natural language, making them easy to grok for both game designers and scripters. For example:

go north
pick up sword
say "Hello, adventurer!"
whisper to NPC "Meet me at the tavern."

These constructs should be declarative, focusing on the what rather than the how of execution. In this sense, they allow a more intuitive style of scripting.

2. Declarative NPC Behavior

NPCs often exhibit scripted behaviors that can be described functionally. Here's a proposed construct for handling NPC actions based on conditions:

when player enters_room {
  say "Welcome, traveler!"
  give map to player
  follow player until leave_room
}

This pattern is declarative and uses event-driven syntax, where the when keyword triggers specific actions when certain conditions are met.

3. Pattern Matching for Commands and Events

Pattern matching allows for flexible input handling, particularly when dealing with different kinds of commands or player interactions:

match command with
  | "go north" => move player north
  | "look at " + target => describe target
  | "pick up " + item => pick_up item

Here, we can bind variables like target and item using simple string concatenation syntax, allowing dynamic handling of a wide range of player actions.

4. Functional Constructs

To maintain functional programming principles, we can introduce lambdas and higher-order functions that are easy to write and understand:

let apply_bonus = (character, bonus) -> character.strength += bonus

let handle_event = (event, callback) -> 
    if event.type == "combat" then
      callback(event)

Here, lambdas are expressed in a natural way, with the arrow (->) denoting function application.

5. Asynchronous Actions

In a MUD game, many actions have delays or are asynchronous (e.g., waiting for an event or a timer). A lightweight async syntax will allow these to be written easily:

wait 3 seconds then
  attack target
wait until enemy leaves_room then
  sneak out quietly

This allows game events to occur asynchronously, without complicating the code. The syntax uses simple constructs like wait for timing.

6. Dynamic State Handling

The game world is highly dynamic, and the language should offer constructs for easily managing state. For example, changing player stats, object properties, or room states could be achieved through functional updates:

update player {
  health += 10
  inventory += sword
}

update room "tavern" {
  occupants -= NPC
}

The use of update here makes state transitions declarative, emphasizing what is being updated rather than focusing on how the update is performed.

Conclusion: Multi-Paradigm Language for a MUD Game

The language proposed here balances functional programming principles with an imperative, command-driven syntax. By focusing on readable and flowing constructs, we aim to create a language that feels natural in a MUD setting, where the narrative and interactions are key. The following are the most important aspects of this language design:

1. Simple command-based syntax for actions like movement, combat, and dialogue.
2. Declarative event handling for scripting NPC behavior and game events.
3. Pattern matching for handling diverse player commands or game inputs dynamically.
4. First-class functions and higher-order functions for more complex game logic.
5. Asynchronous operations expressed through simple, readable constructs.

By emphasizing simplicity and flow, the language becomes accessible to non-programmers while still offering the expressive power needed to manage complex game logic.