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nex

Roadmap

Sixteen phases from lexer to a tagged v0.1.0 release with a package manager, language server, standard library and documentation site. Progress is tracked one micro-step at a time in progress.txt — one micro-step per commit, no skipping ahead.

Current position

Section titled “Current position”
  • last step: 3.11
  • current phase: 4 (Parser: statements & items) — starting
  • next step: 4.1 — let / let mut statements

Phase status

Section titled “Phase status”
Phase Milestone State
0 Foundations done
1 Lexer done
2 AST design done
3 Parser: expressions done
4 Parser: statements & items planned
5 Tree-walking interpreter planned
6 Name resolution + type checker planned
7 Language feature wave 2 planned
8 LLVM backend planned
9 WASM target planned
10 Standard library planned
11 Package manager planned
12 Editor highlighting planned
13 Language server planned
14 Documentation site planned
15 Polish + v0.1.0 planned

What each phase delivers

Section titled “What each phase delivers”
  • 0 — Foundations: workspace, CI, examples, progress tracking.
  • 1 — Lexer: full token stream with error recovery (done; see the lexical structure reference).
  • 2 — AST design: node identity (NodeId), spans, the expression, statement, item, type, and pattern node types, an s-expression pretty printer, and a coverage review against the spec (done; see AST Coverage for what’s still missing).
  • 3–4 — Parser: expressions first, then statements and items, with error recovery and ariadne diagnostics (step 3.11).
  • 5 — Tree-walking interpreter: nex run.
  • 6 — Type checker: name resolution and static typing; language v0.1 becomes real.
  • 7 — Feature wave 2: block comments, character literals, and the other missing pieces; the language spec freezes as v0.1 at the end of this phase.
  • 8–9 — Backends: LLVM native codegen (nex build) and WebAssembly (nex build --target wasm32); all backends must produce identical output on the regression corpus.
  • 10–11 — Standard library and package manager: nex test lands with the stdlib + test runner.
  • 12–14 — Tooling: editor highlighting, language server, and this documentation site.
  • 15 — Polish: formatter (nex fmt), benchmarks, and the v0.1.0 tag.

Deferred / pending

Section titled “Deferred / pending”
  • CI does not yet install LLVM — needed from step 8.2.
  • No benchmarks yet — parser throughput baseline is due at step 4.12.
  • Block comments (/* */) arrive in Phase 7; they currently lex as operators.
  • Character literals ('a') are not in the language.

Design notes that shape later phases

Section titled “Design notes that shape later phases”
  • NodeIds are dense and sequential so they can index side tables directly. Later passes store their results in side tables keyed by NodeId rather than mutating the AST, which stays immutable after parsing.
  • NodeId::DUMMY marks nodes synthesised during error recovery; it panics on .index() so a dummy can never silently corrupt a side table.
  • Memory management is decided in Phase 8. Current plan: automatic reference counting emitted by the code generator for heap values (str, arrays, boxed enums). No ownership or borrow checking in v0.1.