Skip to content

3. Strict engine/shell separation

Date: 2026-06-27

Status

Accepted

Context

Reuse across shells (and the cheap Tauri gate) depends on logic not leaking into platform UI code.

Decisions

Core Logic in Engine

Decision: The engine owns parsing, document/tree model, formatting, JSONPath query evaluation, autocomplete schema inference, and error positions/diagnostics.

Rationale: - Keeps the core logic 100% portable and shell-agnostic.

Rendering and UX in Shell

Decision: The shell owns the view layer only, including the editor's syntax coloring (native tree-sitter on macOS, CodeMirror in Tauri).

Rationale: - UI components (coloring, scroll offsets, cursor state) are highly platform-specific. Diagnostics are rendered by the shell but computed by the engine.

Consequences

  • Everything on the engine side survives a shell swap verbatim.
  • The editor component becomes "just a view," making it replaceable (de-risking ADR-0004).
  • Requires resisting the temptation to do "quick" parsing/validation in Swift.