LINQ Simulator

LINQ Simulator is an interactive C# console application designed to let you experiment with LINQ queries in real time. Instead of writing a full project and recompiling every time you want to tweak a query, this tool uses Roslyn scripting under the hood to dynamically compile and execute your lambda expressions against an in-memory collection of values.

How It Works

Behind the scenes, the program:

• Parses a comma-separated list of inputs (integers, doubles, or strings) and stores them as object values
• Maintains an active "current result" collection, which can be transformed by executing commands like filter, select, orderby, groupby, take, skip, distinct, any, and all
• Supports chaining multiple commands in sequence—every new operation pushes the previous state onto an undo stack, so you can type undo/redo to move backward or forward through your query history
• Allows grouping with aggregates (e.g. count, sum, avg, min, max), and pretty-prints anonymous types or grouped results in the console
• Exports the current result set as CSV or JSON files via a simple export csv or export json command

Dynamic Lambda Compilation

Because it uses Microsoft.CodeAnalysis.CSharp.Scripting, you can write lambdas like:

filter x => (int)x > 10
select x => new { Value = x, Square = ((int)x) * ((int)x) }
groupby x => ((int)x) % 2 count

and see immediate results—no additional compilation steps required.

Project Structure

On the project page, you'll find:

• A single Visual Studio solution with a console-app (Program.cs) that wires up the REPL loop and command parser
• A ScriptOptions setup that pre-loads System.Linq, so all standard LINQ operators (Where, Select, OrderBy, etc.) are available at runtime
• Helper methods for robust error handling (compilation errors are caught and reported, with hints about quoting string literals), plus logic to convert between int/double and string inputs automatically

How to Run

1. Clone the repo and open it in Visual Studio (or any IDE that supports .NET Core)
2. Add the following NuGet packages:
   • Microsoft.CodeAnalysis.CSharp.Scripting (for dynamic lambda compilation)
   • Newtonsoft.Json (for JSON export)
3. Build and launch the console app. You'll be prompted to paste a list of comma-separated values
4. After that, type help to see all available commands

Use Cases

Whether you're learning LINQ for the first time or you simply want a convenient "playground" to prototype queries without writing full data models or setting up a database, LINQ Simulator makes it easy to explore filtering, projection, grouping, sorting, pagination, and more—all in one lightweight console tool.