Project status

Updated: 2026-08-14

Jazz is experimental and pre-1.0. This matrix separates implemented behavior from partial areas and planned work.

Area	Status	Evidence
Source, literals, bindings, lambdas, blocks, and operators	Implemented	Language overview
ADTs, typed patterns, ordered cases, and guards	Implemented	ADTs and patterns
Static exhaustiveness and unreachable-arm analysis	Implemented	Control flow
Type inference, signatures, generic named types, and numeric widths	Implemented	Types and signatures
Modules, import visibility, explicit exports, and cycle diagnostics	Implemented	Module resolution
Interpreter, stable rendering, runtime hosts, and observations	Implemented	Runtime values
Bundled Prelude and explicit-import collection, text, and I/O modules	Implemented	Standard library
Structured errors and opt-in warning policy	Implemented	Diagnostics
Capability declarations and concrete method dispatch	Partial	Capabilities
Name-based purity analysis	Partial	Purity
Jazz-authored lexer, parser, and canonical-core lowering	Partial	Bootstrapping
Typed-core production and backend-neutral IR lowering	Partial	Compiler pipeline
Canonical Jazz-authored semantic compiler	Planned	Roadmap
Native code generation, linking, and runtime	Planned	Roadmap
Stable releases, package ecosystem, and language server	Planned	Roadmap

Partial means that working, tested behavior has an explicit boundary. The typed-core and backend-neutral lowering path currently covers scalar bindings, direct calls, function values, unary closures, lexical capture, higher-order calls, partial application, ordered application of additional arguments, and capture-free, non-escaping direct self and mutual recursion. It also covers closure-shaped self and mutual recursion when every external capture precedes the first group member. These groups reuse one immutable shared environment containing ordered external captures and reconstruct self or peer closures without cyclic initialization. Bounded value-producing conditionals and scalar pattern cases can nest throughout that profile. In value positions, their deterministic multi-block control flow preserves explicit branch and join transport: a case evaluates its scrutinee once, retains source-ordered literal, wildcard, and variable arms, falls through false guards, and keeps variable binders arm-local.

For complete named or lifted function results, the profile records direct and closure tail intent. It propagates that result position through selected conditional branches and bounded scalar-case bodies, which terminate directly without result joins. Conditions, scrutinees, guards, operands, and nested value contexts remain ordinary value positions. Partial applications still return closure values; oversaturated calls tail-terminate only at the final exact stage; and module entry remains ordinary call/join/return lowering. This uses the existing Lowered IR schema, format, and validator and changes neither the runtime ABI, public language semantics, hosted compiler, nor native-stack behavior. The opt-in profile still requires a final unguarded wildcard or variable as its independent lowering-totality boundary; source-level static exhaustiveness and unreachable-arm analysis are implemented under RFC 0012.

Managed Text construction and transport now spans bindings, parameters, results, captures, calls, conditional and scalar-case results, returns, and tail-call operands. The Lowered IR path uses one semantic Text layout and exact pure services for equality, length, append, and append-char; inequality reuses equality followed by Boolean-not. Text-only transport declares no service, and referenced services are deduplicated in fixed catalog order.

Managed patterns and scrutinees remain deferred pending separate matching, projection, and ownership contracts. Pattern-lambda backend lowering remains deferred pending an invocation contract integrated with closures, currying, recursion, and callable identity. Text uncons, from-chars, concat, I/O, collections, later or interleaved external captures, scalar exports, and complete multi-module integration remain excluded. The Text services are not RuntimeHost operations or a native ABI. Ordinary compile and run modes remain on canonical core and the interpreter.