Architecture

High-Level Flow

1. VS Code calls the document formatter provider.
2. Extension reads workspace settings (maxLineLength, dialect).
3. formatExpression() performs dialect-aware parsing.
4. Parsed AST is sent to the deterministic printer.
5. Printer returns canonical text; extension applies a full-document edit.

Dialect Pipeline

• standard: strict JMESPath parse path.
• roarpath: preprocess ~ roots to $, parse with legacy literal support, print root as ~.
• auto: try standard first, fallback to roarpath.

This keeps parsing concerns isolated from printer concerns.

Formatter Invariants

• Idempotent output.
• Stable precedence and parentheses handling.
• Stable wrapping controlled by maxLineLength.
• No evaluation/runtime semantics in formatter logic.

Testing Strategy

• Fixture tests for canonical output.
• Behavior tests for dialect selection and edge-case handling.
• Explicit invalid-input coverage.
• Idempotency checks across fixture outputs.