dotcl 0.1.8

dotcl

Common Lisp implementation on .NET. Lisp source is compiled to CIL (Common Intermediate Language) and runs on the .NET JIT — so the same Lisp image runs on Windows, macOS, and Linux across x86-64 and ARM64 without per-platform porting work.

Broadly conforms to the ANSI Common Lisp standard — verified against the ansi-test suite.

What dotcl is good for

• Embedding Common Lisp in .NET applications. dotcl.runtime is a regular .NET library; you load it from any C# / F# / VB.NET project, evaluate Lisp code, and call back and forth.
• Writing .NET code in Lisp. The dotnet: package gives direct access to .NET types: (dotnet:new "System.Text.StringBuilder"), (dotnet:invoke sb "Append" "x"), (dotnet:static "System.Math" "Sin" 1.0). You can subclass .NET types from Lisp via dotnet:define-class — the compiler emits real .NET classes, so frameworks like MAUI, ASP.NET Core, and MonoGame just see them as ordinary subclasses.
• Cross-platform CL with NuGet ecosystem access. Any NuGet package is reachable from Lisp; any Quicklisp library that doesn't rely on SBCL-only internals tends to work too (asdf, alexandria, etc. are routinely loaded).

Quick start

# Install dotcl as a global .NET tool (works on any host with .NET SDK 10+).
dotnet tool install --global dotcl

# REPL
dotcl repl

# Evaluate a form
dotcl --eval "(format t \"hello, ~a~%\" (lisp-implementation-type))"

# Run a file
dotcl --load my-program.lisp

The framework-dependent dotcl package is portable across OS / arch but JIT-compiles the core on first launch (~3 s cold start). For faster startup, install the RID-specific package — it bundles ahead-of-time (R2R) FASLs:

# Pick the one matching your host:
dotnet tool install --global dotcl.win-x64
dotnet tool install --global dotcl.win-arm64
dotnet tool install --global dotcl.linux-x64
dotnet tool install --global dotcl.linux-arm64
dotnet tool install --global dotcl.osx-x64
dotnet tool install --global dotcl.osx-arm64

The two variants share the dotcl command name, so install only one.

For Roswell users, per-RID tarballs are also published on each release page.

Prerequisites

• .NET SDK 10+ — see install table below

Installing .NET SDK 10

Building from source

If you want to hack on dotcl itself rather than just use it, clone the repo and bootstrap with Roswell:

make cross-compile        # uses Roswell/SBCL to bootstrap the compiler
make compile-asdf-fasl    # pre-compiles ASDF (required by samples)
make install              # builds and installs the local nupkg as `dotcl`

After the first cross-compile, dotcl can self-host: DOTCL_LISP=dotcl make cross-compile rebuilds the compiler using dotcl itself.

Samples

Working integrations in samples/:

• MauiLispDemo — a .NET MAUI app (Windows + Android) where Application / ContentPage / view model are all defined in Lisp via dotnet:define-class.
• AspNetLispDemo — ASP.NET Core controller written in Lisp, with attribute routing.
• MonoGameLispDemo — Game subclass in Lisp; the Draw override runs on the MonoGame frame loop and animates the background colour.
• McpServerDemo — Model Context Protocol server exposing a Lisp REPL to MCP clients (Claude Desktop, etc.).

Each sample's README.md walks through the boot pattern.

Architecture

• Compiler (compiler/, written in Lisp): transforms S-expressions into a flat list of CIL instructions (SIL).
• Runtime (runtime/, written in C#): object representation, reader, CIL assembler (PersistedAssemblyBuilder-based for .fasl output and Reflection.Emit for in-memory codegen), and the standard library functions that aren't expressible in pure Lisp.
• Bootstrap is by cross-compile: a Roswell SBCL runs compiler/cil-compile.lisp to emit compiler/cil-out.sil, which the .NET runtime loads to bring up the Lisp environment. From that point dotcl can rebuild itself.

Architectural detail and design history are in DESIGN.md.

License

MIT. See LICENSE.