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Introduction to G#

G# is a modern, simple, and accessible programming language for .NET. It borrows the approachable shape of Go — packages, imports, func, struct, slices, maps, channels, go, select, and concise top-level programs — while targeting the .NET CLR and the libraries that already exist there.

If you know Go, much of the surface syntax will feel familiar. If you know .NET, G# gives you another way to build managed assemblies, call CLR APIs, use classes, interfaces, properties, events, delegates, exceptions, async workflows, and run under the normal dotnet toolchain.

How G# runs​

G# currently has two execution paths:

  • The production compiler, gsc, parses, binds, lowers, and emits managed PE assemblies directly. SDK projects use this path through MSBuild, so dotnet build and dotnet run work for .gsproj projects.
  • The interpreter path executes the same parsed and bound program in-process. gsc uses this compatibility mode when you pass source files but do not pass /out. It is useful for quick experiments, but some CLR interop features are emit-only. In particular, the interpreter cannot marshal G# function literals into CLR delegates in every place the emitted assembly can.

The default emitted target framework is net10.0; the compiler also recognizes net8.0 and net9.0 target framework mappings.

Who G# is for​

G# is for people who want a small language with Go-inspired clarity and access to .NET libraries. It is especially useful if you want to learn or teach .NET without starting from C#, or if you like Go's direct style but need CLR interop, MSBuild projects, Portable PDBs, and the broader .NET ecosystem.

The language is still growing. The documentation highlights what works today and calls out differences between the compiler and interpreter where they matter.

Where to start​