otter-net

The Otter programming language on a native .NET engine.

Otter is a programming language that reads like plain English. Its released implementation, otterPS, is written in PowerShell. otter-net is a second implementation of the same language in C# (.NET 10, Native AOT): one self-contained otter per platform that starts in tens of milliseconds instead of seconds and needs nothing installed.

Status: release candidate in progress, not released. otter-net runs nearly all of Otter 1.0.1 natively; it is not part of any Otter release yet. Use the released Otter to write programs.

What "the same language" means

• No new syntax and no new features. otterPS's SPEC-DECISIONS.md is the language specification for both implementations.
• Every program must print the same output, the same error messages and exit with the same code as otterPS. tools/compare.ps1 runs programs through both and compares them byte for byte.
• Every feature is native: otter never needs PowerShell (it handed programs to the PowerShell Otter while the port was in progress).

See docs/ARCHITECTURE.md for the design and the plan.

Where it stands

Measured against otterPS 1.0.1 (the frozen reference) on Windows PowerShell 5.1 in CI; details in docs/PORT_DASHBOARD.md.

Language	Every Otter 1.0.1 statement and expression parses and runs in C#: the core language, files, JSON, CSV, XML, bytes, crypto, dates, processes and system integration, databases and queries, HTTP, servers, WebSockets, TCP, TLS, UDP, file watching, the event loop (D130, D133), UI and the web compiler
Programs	All 237 of otterPS 1.0.1's own programs are taken on natively; 257 compared programs, 0 differences
otter web	337 pages compared byte for byte, 0 differences
Commands	every otter command natively; studio (the IDE) is out of scope
Fuzzing	300 generated and mutated programs, 0 differences, all native
PowerShell	not needed: every feature runs in C#, including desktop windows (otter-desktop.exe, WPF) and remote commands (WinRM) on Windows
Speed (Windows, median)	say "Hello": 16 ms (otterPS: 2,332 ms); 22x to 146x faster on the benchmarks, ~2,990x on list-heavy code; peak memory 10-27 MB (otterPS: 233-327 MB)

Platforms

Every commit is built as a native executable and tested on each of these:

Platform	Runtime	Built and tested on
Windows 10/11, Intel and AMD	win-x64	Windows (also compared with otterPS)
Windows 11 on Arm	win-arm64	Windows 11 Arm
macOS, Apple silicon	osx-arm64	macOS
macOS, Intel	osx-x64	macOS Intel
Linux, Intel and AMD	linux-x64	Debian 12
Linux, Arm (Raspberry Pi 4/5, Arm servers)	linux-arm64	Debian 12
Chromebooks	linux-x64 or linux-arm64	Debian 12

Chromebooks run otter in ChromeOS's Linux development environment (Settings > Advanced > Developers > Linux development environment), which is Debian 12: the Linux executable for the Chromebook's processor runs there unchanged. Linux executables are built on Debian 12 so they need nothing newer than its C library, and so also run on current distributions. Managed (school or work) Chromebooks can have the Linux environment turned off by the administrator.

Databases (D97) use the operating system's own SQLite: built into Windows and macOS; on Linux and Chromebooks install it with sudo apt install libsqlite3-0 if a program says SQLite could not be loaded.

No PowerShell is needed on any platform. On Windows, desktop windows run in otter-desktop.exe, installed beside otter; the packages publish it self-contained, so no .NET runtime is needed either (a development build from tools/publish.ps1 is framework-dependent and needs the .NET 10 Desktop Runtime).

Building

dotnet build otter-net.sln -c Release
dotnet src/Otter.Cli/bin/Release/net10.0/otter.dll run hello.ot

tools/publish.ps1 makes the native executable; tools/package.ps1 makes the (unsigned, unpublished) packages and installers - the current internal preview is 0.9.0-preview.1, see docs/PACKAGING.md, docs/PREVIEW_RELEASE.md and docs/SIGNING.md. tools/compare.ps1 -OtterPs <otterPS checkout> -OtterNet <otter.dll or otter.exe> compares the two implementations.

License

Otter Free Use License 1.1 - free to use; source-available, not open source. See LICENSE.