Missing Features (v0.1 Gap Analysis)

This document lists features, modules, and behaviors described in the AIVI Language Specification vs. the v0.1 Rust Implementation.

Note to Users: AIVI v0.1 is primarily an interpreted language embedding a CST-to-Kernel pipeline. Native Rust code generation exists as an experimental backend that emits standalone Rust logic for a limited subset of AIVI (see Native Codegen below). The interpreter remains the most complete backend today.

1. Syntax & Language Features

Feature	Spec Section	Implementation Status	Notes
Generators	Generators	Implemented	Desugared to Church-encoded lambdas in kernel.rs. generate blocks supported. loop/recurse inside generators partial.
Decorators	Decorators	Implemented (Syntax)	Parsed and validated; only standard decorators allowed.
User-defined Domains	Domains, Units, and Deltas	Implemented	DomainDecl exists in CST/HIR.
Patching	Patching Records	Implemented	Patch alias exists; desugaring logic present.
or fallback	Effects: or fallback	Implemented	Fallback-only sugar for Effect (after <- in effect {}) and Result (expression form).

2. Type System

Feature	Spec Section	Status	Notes
Higher-Kinded Types	The Type System	Structurally Implemented	Kind enum (Star/Arrow) and builtins (List: *->*, Effect: *->*->*) exist in checker.rs. Complex inference scenarios may vary.
Row Polymorphism	The Type System	Implemented	Open records and row extension/restriction logic present in checker.rs.
Effect Typing	Effects	Implemented	Effect E A is a first-class type; attempt/pure/fail are built-ins.

3. Standard Library Status

Module	Status	Backend
aivi.regex	Implemented	Backed by runtime/builtins/regex.rs.
aivi.i18n	Implemented (Minimal)	Properties catalogs + key/message sigils + placeholder type checking. Placeholder rendering uses the runtime's default formatting (locale-neutral; no CLDR/ICU formatting in v0.1).
aivi.net.http	Implemented	Backed by runtime/url_http.rs.
aivi.net.server	Implemented	Backed by runtime/http.rs (using aivi_http_server).
aivi.db	Partial	database.rs exists in stdlib/runtime, likely SQLite wrapper.
aivi.math	Implemented	Extensive math.rs in stdlib.

4. Tooling & Execution

Component	Status	Notes
Native Codegen	Experimental (Partial)	aivi build can emit standalone Rust logic via [build].codegen = "native". Current limitations include incomplete builtins/stdlib coverage plus gaps in native runtime feature coverage (e.g. some index paths and raw expressions).
Package Manager	Implemented (Minimal)	Cargo-backed search/install plus package/publish wrappers. Dependency installs validate [package.metadata.aivi] and enforce kind = "lib"; publishing validates aivi.toml ↔ Cargo.toml metadata consistency.
LSP	Implemented	aivi_lsp crate exists with diagnostics, formatting, and definition lookup.

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Walkthrough: The v0.1 Reality

If you are using AIVI v0.1 today, you are using a high-integrity interpreter.

1. The Code is the Truth: The crates/aivi/src/ directory contains the definition of the language.

   • syntax.rs / cst.rs define what you can write.
   • checker.rs defines a surprisingly capable type system (HKTs, Classes, Rows).
   • runtime/ implements the "magical" effects and IO.

2. Performance:

   • Code is lowered to a Kernel IR and interpreted.
   • It is fast enough for scripting, servers (via Tokio integration), and tooling.
   • It is not yet generating optimized WASM for high-performance compute, though the type system allows expressing it.

3. The "Rust" Target:

   • When you run aivi build, you get a Rust binary (via cargo).
   • With codegen = "embed", the binary contains your HIR program as JSON and runs it via the interpreter runtime.
   • With codegen = "native", the generated Rust corresponds to the AIVI logic directly (experimental; partial coverage).