NVR

Nested Variable Resolution for mustache-style template strings.

nvr resolves template strings containing variables like {{variable}}, with full support for recursive nesting such as {{kv.{{proto}}_backend}}. It bridges mst-parser for template structure and varchain for flexible, async variable lookups.

Features

• Nested Resolution: Resolve variables whose keys are themselves templates (e.g., {{prefix_{{id}}}}).
• Async Lookup: Integrated with varchain for non-blocking, chainable variable sources.
• Safety Limits: Configurable recursion depth and result size limits to prevent resource exhaustion.
• Injection Protection: Prevents malicious variable injection by validating resolved keys.
• Flexible Missing Logic: Choose between returning original tags, empty strings, or errors for missing variables.
• no_std Support: Compatible with no_std + alloc environments.

Usage Examples

Check the examples directory for runnable code:

• Simple Resolution: examples/simple.rs - Basic variable lookup.
• Nested Resolution: examples/nested.rs - Resolving variables within variables.
• Not Found Handling: examples/not_found.rs - Different behaviors for missing variables.
• Limits & Safety: examples/limits.rs - Depth and size limit enforcement.

Installation

[dependencies]
nvr = { version = "0.1", features = ["full"] }

Feature Flags

License

Released under the MIT License © 2026 Canmi