deltin-rs

deltin-rs is a standalone Rust library and CLI for the DeltinScript / OSTW language surface. It parses, type-checks, and lowers DeltinScript projects to Overwatch Workshop code without requiring external .NET runtimes.

While Wright and external editors consume deltin-rs through native Rust APIs or LPP, the compiler and semantic analyzer operate independently.

deltin-rs owns DEL/OSTW syntax, project loading, semantic analysis, type checking, runtime lowering, and source reconstruction. Shared Workshop semantics, catalog identities, and emission remain delegated to workshop-rs.

DEL / OSTW source
    ↓
deltin-rs parsing / project loading / semantic analysis
    ↓
DEL semantic model / typed HIR
    ↓
deltin-rs runtime + compiler lowering
    ↓
workshop-rs canonical Program / validation / emission
    ↓
Workshop text

The reverse direction starts with Workshop parsed by workshop-rs and uses deltin-rs-owned reconstruction logic to produce useful DEL/OSTW source.

Key features

• Recoverable parsing: retains authored text, comments, trivia, and exact locations for accurate diagnostics and refactoring tools.
• Project resolution: deterministic multi-file import handling and project discovery.
• Semantic analysis: scoping, type inference, method overloads, classes, structs, enums, interfaces, and virtual dispatch.
• Typed representation: high-level semantic model that stays backend-neutral until lowering.
• Semantic queries: symbol, reference, and type lookups for editors and Wright.
• Workshop code generation: lowers DEL HIR into the canonical workshop-rs Program model with explicit error reporting for unsupported runtime behavior.
• Verified compatibility: validated against corpus fixtures, oracle snapshots, and differential tests.

Compatibility

For the declared support surface, compiled Workshop output converges structurally on the pinned upstream OSTW compiler output (rule order, element identities, control flow, conditions, values, variable names and indices, and element cost) when both outputs are parsed as canonical Workshop programs; formatting is not compared. Source analysis and tooling surfaces target observable DeltinScript / OSTW semantics, not upstream compiler architecture.

Capability	Status	Notes
Syntax & parsing	✅ Supported	Recoverable parser with source/trivia evidence
Projects & imports	✅ Supported	Multi-file import resolution; project/compiler surfaces continue to expand
Type checking	✅ Supported	Scoping, overload resolution, access control
Classes, structs & enums	✅ Semantic support	High-level semantics exist; some concrete Workshop runtime lowering remains incomplete
Inheritance / virtual dispatch	✅ Semantic support	Concrete runtime lowering is still being closed
Generics / lambdas / pattern matching / recursion	✅ Semantic support	End-to-end Workshop behavior remains evidence-gated where applicable
Embedded Workshop / lobby data	🟡 Partial	Canonical Workshop contracts are still being integrated
Workshop builtins	🟡 Partial	Canonical catalog binding exists; breadth and lowering continue to expand
DEL/OSTW → Workshop compilation	🟡 Partial	Core HIR→Program lowering exists; advanced runtime/project surfaces are incomplete
Workshop → DEL/OSTW reconstruction	⏳ Not yet	Will consume canonical workshop-rs semantics and remain owned by deltin-rs

Exact implementation evidence lives in the machine-readable support matrix; see docs/compatibility.md for methodology and state meanings. The matrix records current support; it does not define which established upstream core-language features belong in scope.

CLI and library

Rust embedding uses the deltin-rs package and does not pull CLI-only dependencies such as clap or clap_complete. Install the executable package from source with cargo install --path cli.

deltin-rs check <file-or-dir> [--json]
deltin-rs inspect <file> <line>:<col> [--json]
deltin-rs support [--check] [--json]
deltin-rs dev parse <file> [--json]
deltin-rs dev hir <file-or-dir> [--json]
deltin-rs completion <bash|zsh|fish|powershell>
deltin-rs maintainer compatibility [--json]

The standalone semantic/tooling path does not require Wright. Workshop-dependent compilation uses the released workshop-rs library. See docs/architecture/README.md for the current architecture and dependency boundary.

Relationship with Wright

deltin-rs owns the syntax, type system, and AST for DeltinScript. Higher-level tools such as Wright consume these semantic results to provide cross-language refactoring, linting, and language server capabilities without modifying compiler internals.

Building

Requirements: Rust 1.85+.

cargo build --workspace --release
cargo test --workspace --all-targets

Validation

Before claiming implementation work complete, run the repository quality gates and the affected compatibility/corpus checks. Real-project support claims must also be revalidated against the relevant full project rather than inferred from unit-test counts alone.

Documentation

Current architecture, compatibility/evidence, interfaces, provenance, limitations, and maintainer references are indexed in docs/README.md.

Contributing

This repository is part of the WrightKit multi-repository workspace. Apply the workspace-level AGENTS.md first, then this repository's local AGENTS.md.

License

deltin-rs is distributed under the MIT license. Compatibility fixtures retain their recorded upstream provenance and licensing.