Question 1

How does O'Doyle compare to Clara Rules?

Accepted Answer

O'Doyle uses tuple-based facts for automatic updates and unified rules/queries, making it more flexible for fine-grained state, but lacks Clara's truth maintenance and may be slower without optimization. Choose O'Doyle for simplicity in reactive logic, and Clara for advanced features like accumulators.

Question 2

How to avoid infinite loops when updating facts in O'Doyle?

Accepted Answer

Use `{:then false}` or custom functions like `{:then not=}` on tuples in the `:what` block to prevent rules from triggering on self-updates. For example, in the move-player rule, adding `{:then false}` to position tuples stops infinite recursion.

Question 3

What are derived facts and when should I use them?

Accepted Answer

Derived facts are created from query results within rules using `:then-finally` blocks, enabling accumulators and computed state. They improve performance by reducing joins but require careful design to avoid non-reactive updates, as shown in the characters-within-window example.

Question 4

Can O'Doyle handle large datasets efficiently?

Accepted Answer

Yes, but performance depends on rule design; bulk changes with derived facts can optimize joins. However, out-of-the-box, it may be slower than Clara, so benchmark with tools like the provided dungeon benchmark for specific use cases.

Question 5

How do I serialize and restore a session in O'Doyle?

Accepted Answer

Use `query-all` to extract plain fact tuples, filter out derived facts, and save them as EDN. Restore by reading the EDN and inserting facts into a new session, as detailed in the serialization section, ensuring compatibility across versions.

Question 6

Is O'Doyle suitable for building web UIs?

Accepted Answer

Yes, it's ideal for reactive UIs with complex state dependencies, and libraries like O'Doyle Rum integrate it with web frameworks. However, debugging can be challenging due to the data-driven nature, so use `wrap-rule` for logging.

Question 7

How to define rules dynamically at runtime in O'Doyle?

Accepted Answer

Use the `->rule` function instead of the `ruleset` macro to create rules based on runtime data. For example, define a function that returns a rule with a dynamic `:what` block, allowing for flexible, programmatic rule generation.

O'Doyle Rules

What is O'Doyle Rules?

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