7 releases

Uses new Rust 2024

new 0.3.3	May 9, 2026
0.3.2	May 9, 2026
0.2.1	May 3, 2026
0.1.1	Apr 26, 2026

#38 in Programming languages

MIT license

460KB
7.5K SLoC

axon-lsp

Language Server Protocol implementation for the Axon programming language. A single Rust binary that speaks LSP and, by construction, works in VSCode, Claude Code, Cursor, Antigravity, Zed, Neovim — or anything else that speaks LSP — with no per-IDE work.

Status: v0.3.0 released — published on crates.io with axon-frontend = "0.3" as a registry dep. v0.3.0 lifts the capability surface past the rust-analyzer / pyright "core" baseline with eight new LSP-spec features (signature help, document highlight, folding, smart-select, code lens, call hierarchy, on-type formatting, pull diagnostics) plus cancel-aware workspace fan-outs and two new code actions. Roadmap and Resultado blocks for every sub-fase live in docs/plan_v0.3.0.md; historical plans sit in docs/plan_v0.2.0.md and docs/plan_v0.1.0.md. Install via cargo install axon-lsp, download from GitHub Releases, install the VSCode extension, or build from source — see docs/integrations/install.md.

What it does

Capability	Behavior
`publishDiagnostics`	Lex / parse / type errors with `axon-{lex,parse,type}` source tag and precise ranges (whole identifier for type errors, single char for punctuation)
`hover`	Markdown — local declarations show kind + signature; outer doc comments (`///`, `/** */`) attached to channel decls render as a Markdown paragraph above the signature; built-in types (`String`, `Channel`, `Trusted`, …) and syntax keywords pull rich docs from the embedded corpus
`definition`	Zero-width Location at the declaration's keyword
`documentSymbol`	Outline tree with sensible `SymbolKind` per declaration kind
`completion`	Context-aware: inside a type annotation surfaces only types, in declaration name slots stays out of the way, default context offers keyword snippets + user decls + built-in types with `lsp-docs` documentation attached
`references`	File-local + workspace-wide. Walks every TypeExpr-bearing site (type field types, flow params, return types, intent output types) with `Loc`-precise ranges; cross-file scan reads in-memory snapshots first, falls back to disk parses
`prepareRename` + `rename`	Workspace-wide atomic `WorkspaceEdit`. D8 rejections pinned in code: built-in types, declaration keywords, stdlib symbols, and identifiers absent from the workspace index reject with stable user-facing messages
`documentSymbol` + `workspace/symbol`	The latter is a substring-match query against an index of every `name → DeclLocation` the server has seen in any `.axon` file under workspace folders
`semanticTokens/full`	LSP standard registry mapping — types, functions, variables, parameters, properties, decl keywords, with `declaration` / `readonly` modifiers. The TextMate grammar still paints lexical concerns (strings, numbers, regular comments) so the two layers don't double-paint
`inlayHint`	Inferred type after `let` literal RHS — `: String`, `: Integer`, `: Float`, `: Bool`. Range filter respected so off-screen lines don't ship hints
`codeAction`	Quick fixes (kind = `quickfix`): Rename to typo candidate (Levenshtein-≤2 against the workspace decl name set on `Undefined <kind> 'NAME' …`, up to 3 candidates), Insert missing `}` (zero-width insertion on `Expected RBrace, found …`), Add missing field (matcher ready for `axon-frontend 0.4` — fires on `… field 'F' … type 'T' …` shape and inserts `F: Any` after the type's last existing field). Refactors (kind = `refactor.rewrite`): Make `T` optional — cursor-driven, appends `?` to a non-optional type expression, idempotent on already-optional types
`formatting`	Token-level passthrough through the `axon-fmt` crate. Right-trims trailing whitespace per line + ensures exactly one trailing `\n`. Comments survive verbatim across all six kinds (`//`, `/* /`, `///`, `/* /`, `//!`, `/! */`) thanks to the Fase 14 trivia channel. Mirrors `axon fmt` in `axon-lang` v1.9.0+ for byte-identical output
`onTypeFormatting`	Trigger: `}`. Surfaces only the line edits within `[pos.line, pos.line + 2]` so the user's keystroke flow isn't fought by full-document rewrites. Same idempotence + comment-round-trip guarantees as `formatting`
`signatureHelp`	Pops the flow's signature label + active-parameter highlight when the cursor sits inside `run FlowName(arg1, arg2
`documentHighlight`	File-local — every occurrence of the symbol under the cursor with `WRITE` for the declaration and `READ` for each use. Reuses the `references` AST walker via a `RangeKind`-aware variant
`foldingRange`	Three families: top-level decl bodies (`region`), multi-line block comments (`comment`), and runs of three or more consecutive line comments (`comment`). Walker skips strings + every comment shape so `{` / `}` inside `"…"` or `// …` don't open frames
`selectionRange`	AST-driven smart-select expansion with strict-nesting filter: program → decl → field/parameter → type-expr (full extent including generic param + `?`) → word. Multi-cursor supported (LSP allows `Vec<Position>` per request)
`codeLens`	One `N references` lens per top-level declaration. Click invokes `editor.action.showReferences` pre-populated with the workspace-wide use locations. `0 references` lenses are intentionally omitted (D3 — no `0 references` noise). `resolve_provider: false` so each lens ships complete from the first pull
`prepareCallHierarchy` + `incomingCalls` + `outgoingCalls`	Limited to call-able kinds (flow, persona, tool — D6 conservative scope). Top-level `run` statements surface as synthesised callers with kind `EVENT`; flow bodies with `step.persona_ref` / `use_tool.tool_name` references surface as flow callers. Outgoing only fires for flows
`diagnostic` + `workspace/diagnostic` (LSP 3.17 pull)	Advertised alongside push. When the client advertises `textDocument.diagnostic`, the server flips into pull mode for every URI — `did_open` and the debounced reparse stop publishing push notifications. `workspace/diagnostic` walks the union `workspace_index.all_uris ∪ doc_store.open_uris` so parse-error files (which never reach the index) still surface their diagnostics
`window/workDoneProgress` (workspace scan)	Wraps the recursive `.axon` discovery + parse pass on `initialized`. Lifecycle: `workDoneProgress/create` → `Begin` → throttled `Report` (~20 reports per scan, message `"42 / 200 — file.axon"`) → `End`. Older clients that don't ack `create` get the scan without the lifecycle — graceful degradation, never blocks
Cancel-aware workspace fan-outs	Five long-running handlers (`references`, `rename`, `code_lens`, `incoming_calls`, `workspace_diagnostic`) yield via `tokio::task::yield_now()` between iterations so tower-lsp's drop-on-cancel semantics actually preempt stale requests. The user navigating away mid-scan no longer pays for the rest of the work
`axon/askAdvisor` (opt-in)	Custom LSP method backed by Anthropic's Messages API. Two-axis gate: build with `--features llm` AND set `AXON_LSP_LLM_ENABLED=1` + `ANTHROPIC_API_KEY=…`. Default builds reply with `MethodNotFound`; the deterministic stack is unaffected by either gate.

Editor integrations

Single binary, every editor. Pick yours and follow the doc:

VSCode — docs/integrations/vscode.md (extension source)
Cursor — docs/integrations/cursor.md
Antigravity — docs/integrations/antigravity.md
Zed — docs/integrations/zed.md
Neovim — docs/integrations/neovim.md
Claude Code — docs/integrations/claude-code.md

docs/integrations/README.md carries the index plus the canonical 4-check smoke-test program every editor must light up.

Architecture

crates/
  axon-lsp/   # binary, tower-lsp bootstrap + every LSP handler
  lsp-core/   # logic — pure, sync, no I/O
              #   document.rs (rope), diagnostics.rs (range scanner),
              #   hover.rs, definition.rs, completion.rs (context heuristic),
              #   symbols.rs (DeclMeta + outline), text.rs (shared helpers),
              #   frontend.rs (axon-frontend shim),
              #   workspace.rs (cross-file decl index), references.rs,
              #   rename.rs, semantic_tokens.rs, inlay_hints.rs,
              #   code_actions.rs, formatting.rs (axon-fmt shim),
              #   signature_help.rs, document_highlight.rs,
              #   folding_range.rs, selection_range.rs, code_lens.rs,
              #   call_hierarchy.rs (v0.3.0 capability completeness)
  axon-fmt/   # token-level lossless formatter, consumed by `lsp-core`
              # via workspace dep + invoked by `textDocument/formatting`.
              # Mirrors `axon fmt` in `axon-lang` v1.9.0+
  lsp-docs/   # 18+ Markdown entries embedded at compile time via build.rs;
              # zero runtime deps, lookups hit `&'static str` slices
  lsp-llm/    # opt-in advisor, feature = "llm";
              # default builds keep `reqwest` out of the binary entirely
              # — pinned by an executable smoke test that scans the
              # release binary for forbidden symbol bytes
editors/
  vscode/     # TypeScript extension; spawns the binary, attaches
              # the editor's selection as advisor context, ships
              # commands + snippets
docs/
  plan_v0.2.0.md       # the live roadmap + Resultado blocks (current)
  plan_v0.1.0.md       # historical, kept for traceability
  fase_14_lossless_lexing.md  # upstream reference doc for the
                               # trivia channel `axon-fmt` consumes
  style.md             # canonical Axon style — what the formatter
                       # changes (and what it deliberately doesn't)
  integrations/        # one self-contained doc per editor

lsp-core and lsp-docs keep cargo tree --edges normal empty of tokio / axum / sqlx / aws-* / reqwest / hyper / jsonwebtoken — verified in CI on every commit. The Fase 12.c contract (frontend with zero runtime deps) holds end-to-end into the LSP binary.

Build

Rust 1.95.0 stable (pinned by rust-toolchain.toml).

cargo build --workspace --release
cargo test --workspace

The advisor crate is excluded from the default build:

cargo build --workspace --release --features axon-lsp/llm

Releases

Releases page publishes:

3 platform archives (linux-x86_64, macos-arm64, windows-x86_64) — one binary each.
SHA256SUMS — combined integrity-verification list.

macOS Intel (x86_64-apple-darwin) builds from source (cargo install axon-lsp) until a cross-compiled / self-hosted target lands in a later release.

Auto-generated release notes summarise the commits since the previous tag. The full v0.1.0 story lives in CHANGELOG.md and the per-sub-fase Resultado blocks in docs/plan_v0.1.0.md.

Contributing

axon-lsp is adopter-agnostic — it serves the Axon language the same way rust-analyzer serves Rust. No customer or tenant names appear in code, tests, fixtures, or docs. Details in CONTRIBUTING.md.

License

MIT — see LICENSE.

Dependencies

~16–25MB
~370K SLoC