Installation

Cel.NET targets .NET 10 and uses C# 14 language features (records, init-only properties, collection expressions, pattern-matching enhancements). The project layout is five small assemblies with no required external dependencies.

Prerequisites

• .NET SDK 10.0 or newer
• Any operating system that runs .NET 10 (macOS, Linux, Windows)

NuGet packages

The runtime ships as five packages plus an optional extensions bundle:

Package	What it contains
DotnetCel	Public façade: CelExpression, CompiledProgram. Depends on the next four.
DotnetCel.Core	AST, type system, value model, ITypeProvider / ICelExtension interfaces.
DotnetCel.Parser	Lexer + Pratt parser, macro expansion.
DotnetCel.Checker	Type checker, declarations, overload resolution, CelEnv.
DotnetCel.Runtime	Tree-walking evaluator, activations, POCO adapter, stdlib.
DotnetCel.Extensions	Optional: strings, math, encoders, sets, optionals, bindings, network, block.

Install via the .NET CLI:

dotnet add package DotnetCel
dotnet add package DotnetCel.Extensions   # optional

DotnetCel transitively pulls in DotnetCel.Core, DotnetCel.Parser, DotnetCel.Checker, and DotnetCel.Runtime, so most projects only need the first one.

Project file

If you prefer hand-editing your .csproj:

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>net10.0</TargetFramework>
    <Nullable>enable</Nullable>
    <LangVersion>preview</LangVersion>
  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="DotnetCel" Version="0.1.*" />
    <PackageReference Include="DotnetCel.Extensions" Version="0.1.*" />
  </ItemGroup>
</Project>

Nullable is recommended (the API is null-aware), and LangVersion=preview lets you take advantage of C# 14 features in your own glue code.

Smoke test

Drop this in Program.cs:

using DotnetCel;
using DotnetCel.Types;

var env = CelEnv.NewBuilder()
    .Variable("name", CelTypes.String)
    .Build();

var program = CelExpression.Compile("'hello, ' + name", env);

Console.WriteLine(program.Eval(new Dictionary<string, object?> { ["name"] = "world" }));
// hello, world

Run it:

dotnet run

If you see hello, world, you’re set. Continue with Hello, world for a real walkthrough.