Osprey for VS Code

Preview. Osprey is an alpha language and the extension follows the compiler's current feature set.

Language support for Osprey — a functional programming language with inferred types, algebraic effects, fiber-based concurrency and pattern matching.

Osprey has two source flavors. Default (.osp) uses braces, fn and familiar function calls. ML (.ospml) uses layout, currying and whitespace application. Both lower to the same AST before type checking and compilation.

Select a flavor per file with its extension or a leading // osprey: flavor=ml marker. The compiler also accepts --flavor ml for a single-file build. Multi-file cross-flavor imports remain under development.

Powered by a Rust language server (osprey lsp, built on lspkit) that runs the compiler front-end in-process — the same engine targeted at Neovim and Zed next.

Features

• Syntax highlighting — keywords, types, string interpolation ("Hello ${name}!"), operators, and comments. Default (.osp) is fully supported; ML (.ospml) support follows the compiler's current ML parser.
• Live diagnostics — errors and warnings from the Osprey compiler as you type, inline in the editor.
• Hover, go-to-definition, find-references, document symbols, signature help, and completion — driven by the compiler's own parser and type checker.
• Compile & run from the editor:
  • Osprey: Compile Osprey File (Ctrl/Cmd+Shift+B)
  • Osprey: Compile and Run Osprey File (F5)
• Test Explorer — *.test.osp / *.test.ospml files and their cases appear in the Testing view, with three run profiles: Run, Coverage, and Profile (runs the suite under the sampling CPU profiler and opens its flame graph plus inline heat annotations).
• Documented tests — a /// block (or ML (** … *)) above a test(...) case shows as the case's description in the Testing tree, renders in full when you hover the test(...) call, opens as Markdown via Osprey: Show Test Documentation, and leads the failure message when the case fails.
• Bracket matching, auto-closing, and comment toggling.

Requirements

The extension bundles a version-matched Osprey compiler for your platform and verifies it at startup. Syntax checking does not require a separate compiler installation.

To compile and run programs, Osprey invokes LLVM and a C toolchain, so install:

• LLVM/clang — brew install llvm / scoop install llvm
• MinGW gcc on Windows for runtime linking (scoop install gcc)

Or install the full toolchain via a package manager (this also puts osprey on your PATH):

brew install nimblesite/tap/osprey            # macOS / Linux
scoop bucket add nimblesite https://github.com/Nimblesite/scoop-bucket && scoop install osprey   # Windows

Settings

Links

• Website & docs: https://ospreylang.dev
• Source & issues: https://github.com/Nimblesite/osprey

License

See LICENSE.