obitools4/autodoc/docmd/pkg/obitax/default_taxonomy.md

ObiTax: Default Taxonomy Management

This Go package (obitax) provides utilities for managing a default taxonomy instance, enabling centralized configuration and safe fallback behavior.

Core Features

• ✅ Singleton-style default taxonomy: A single global Taxonomy instance can be designated as the default via .SetAsDefault().

• ✅ Thread-safe access: Uses sync.Mutex (implicitly via package-level variable usage) to ensure safe concurrent writes when setting the default.

• ✅ Graceful fallback with .OrDefault():

  • If a Taxonomy receiver is nil, the method automatically substitutes it with the default taxonomy.
  • Supports optional panic on failure (panicOnNil) if no default is defined.

• ✅ Utility checks:

  • HasDefaultTaxonomyDefined() → returns whether a default is currently set.
  • DefaultTaxonomy() → retrieves the current global instance (if any).

Design Intent

• Promotes configuration reuse and reduces boilerplate in client code.
• Supports robustness: avoids nil dereferences by allowing fallback to a globally configured taxonomy.

Usage Pattern

tax := NewTaxonomy("my-tax")
tax.SetAsDefault() // Now all `nil` receivers will resolve to this instance
result := someNilTax.OrDefault(true) // Uses default; panics only if none exists