CSharpPlayground (FrySharp)

CSharpPlayground (standalone executable: FrySharp) is an interactive multi-language code studio, polyglot Jupyter-style notebook environment, and script automation engine for .NET 10, Python, Rust, and extensible language toolchains built with Avalonia UI.

It operates both as:

1. A Standalone Desktop Application (FrySharp): Native desktop app for macOS (.dmg) and Windows (.msix / .exe installer) with an authentic VS Code-inspired 5-zone IDE layout.
2. A FryPDF Ecosystem Plugin (com.frypdf.plugin.csharpeditor): Edge-to-edge full-viewport workspace studio and document automation plugin for FryPDF.

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🎬 Product Demo

▶️ Click here to watch the FrySharp Demo on YouTube — Supports C#, Python, Rust, Go, Java, C++, JavaScript, F# & SQL

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🌟 Key Features

• Authentic VS Code Layout & Ergonomics:
  • Activity Bar: Explorer, Search, Run & Debug, Package & Dependency Manager (NuGet, pip, npm), Scratchpad, and Problems badges.
  • Primary Side Bar: Multi-language file tree, project explorer, and script management hub.
  • Multi-Tab Editor: Smooth horizontal tab bar with dirty indicators (●), quick close, and isolated execution states.
  • Bottom Tool Deck: Problems (Roslyn diagnostics and external language tracebacks with quick-fixes), Output, Terminal Console (with interactive stdin), Debug REPL, and Rich Results.
  • Status Bar: Execution timer (⏱ 14ms), line/column coordinates, spaces, UTF-8, active language & toolchain status (C# (.NET 10 Roslyn), Python 3.12 (.venv), etc.), and compiler status.
• Interactive Jupyter-Style C# Notebooks:
  • Stateful cell execution kernel chaining submissions using Roslyn Scripting API.
  • NuGet package resolution directly in scripts (#r "nuget: ...").
  • Rich output display: text, images, charts, and custom Avalonia controls (Display.Image(...), Display.Control(...)).
  • Cell input/output collapsing, folding, and export.
• Polyglot Notebooks & Multi-Language Support:
  • Nine Languages: Full multi-language execution and editing for C# (.NET 10 Roslyn), Python (3.9+), JavaScript (Node.js), Java (JDK 17+ / JShell), C++ (C++20 via Clang, GCC, MSVC), Go, F#, SQL (SQLite) and Rust (rustc / Cargo 1.70+).
  • Native C++ & Zero-Config Display Runtime: .cpp files compile with -std=c++20, include <fry/display.hpp> out of the box for interactive table and image dumps, and support native DAP debugging via lldb-dap.
  • Rust with Cargo: .rs files build as a generated Cargo package that points at the file where it is (so mod x; siblings, compiler messages and debug info all name the real file). Crates come from comments such as // #crate: rand = "0.8" (also // #edition: 2024, // #profile: release) and are compiled once into a build folder shared by every script; fry::table(&rows, "Title") and fry::dump!(value) put tables in the Results deck with no setup; rustc's messages land in Problems at the right line and column, with an "Install crate" quick-fix; debugging runs on lldb-dap with Rust's own pretty-printers. Static completion and hover come with the editor; a rust-analyzer client can replace them later through EditorAssistants.
  • Rust notebooks: each cell is built and run; functions, types, imports and macros a cell defines stay for the cells after it, the value of a cell's last expression is shown (a list of structs as a table), ? works, and a variable made with let stays for the cells after it, with its type and any changes made to it (numbers, text, lists, options, tuples, maps and sets are kept; a struct of your own, a closure or a reference isn't, and a later cell that needs one is told why it's gone). fry::share!(x) keeps a value as data for #!share --from rust x in other languages.
  • Polyglot Interactive Notebooks: Mix cells in C#, Python, JS, Java, C++, Go, F#, SQL and Rust in a single notebook document. Cross-language data sharing via #!share --from <lang> <var> converts primitives, vectors, and tables across kernel boundaries as JSON.
  • Intelligent Toolchain Discovery: Automatic detection of project virtual environments, Homebrew, Xcode, MSVC, JDKs, and system PATH with actionable missing-toolchain guidance. See docs/adding-a-language.md and docs/kernel-protocol.md.
• Tabular Data Analytics:
  • Native display and profiling for DataTable, DataView, and Microsoft.Data.Analysis DataFrame.
  • Column summaries, data types, row counts, and inline search.
• Real-Time Roslyn Diagnostics:
  • Debounced (350ms) background analysis via Microsoft.CodeAnalysis.CSharp.
  • "Problems" drawer with error/warning counts, line/column coordinates, and click-to-jump navigation.
• Interactive Debugging:
  • Visual gutter breakpoints, line highlighting, and stepping controls (F5 Continue, F10 Step Over, F11 Step Into, Shift+F5 Stop).
  • Variable inspector and immediate REPL evaluation.

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🚀 Quick Start

Prerequisites

• .NET 10 SDK
• Optional: Python 3.9+ for .py files and Python notebook cells

Run Standalone Desktop App (FrySharp)

# Clone the repository
git clone https://github.com/PrashantUnity/CSharpPlayground.git
cd CSharpPlayground

# Run standalone desktop app
dotnet run --project Runner/CSharpEditorPlugin.Runner.csproj

Run Automated Unit Tests

# Run the unit tests (the real-Python ones run when Python 3.9+ is installed)
dotnet test CSharpEditorPlugin.slnx

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📦 Solution Structure

CSharpPlayground/
├── CSharpEditorPlugin.slnx         # Modern XML solution (Engine + Runner + Tests)
├── CSharpEditorPlugin.csproj       # Core Studio & Plugin library (.NET 10)
├── CSharpEditorPlugin.cs           # IFryPlugin entrypoint
├── plugin.json                     # FryPDF marketplace manifest
├── Controls/                       # VS Code activity bar, status bar, tabs, editor
├── Models/                         # POCO models for scripts, cells, diagnostics
├── Services/                       # Roslyn compiler, kernel, completion, debugger
│   ├── Languages/                  # Language registry and one module per language (Python/Kernel: the kernel program; Rust: Cargo, fry, lldb-dap)
│   ├── Toolchains/ Processes/      # Finding installed toolchains; running programs (stdin, Stop, cleanup)
│   └── Kernels/ Packages/          # Notebook kernels per language, #!share, the kernel protocol; pip
├── ViewModels/                     # Reactive MVVM view models
├── Views/                          # Avalonia XAML views (Studio, Notebook, Manager)
├── Runner/                         # Standalone desktop executable (FrySharp)
│   ├── CSharpEditorPlugin.Runner.csproj
│   ├── Program.cs / App.axaml
│   └── MainWindow.axaml
├── Tests/                          # Comprehensive xUnit test suite (2,100+ tests; Real*/ folders need each real toolchain: Python, Rust, Go, Delve, netcoredbg…)
│   └── CSharpEditorPlugin.Tests.csproj
├── tools/UiSnapshots/              # Headless renderer: real views to PNG, for checking UI changes
├── docs/                           # Developer guides: headless UI snapshots, adding a language, the kernel protocol
└── packaging/                      # macOS DMG & Windows MSIX/Inno packaging assets

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🏗 Architecture: Stateful Notebook Execution

flowchart TD
    subgraph Notebook UI
        C1["Cell 1: var m = 10;"]
        C2["Cell 2: Console.WriteLine(m * 2);"]
        C3["Cell 3: Display.Image(surface.Snapshot());"]
    end

    subgraph "NotebookExecutionKernel (Persistent Session)"
        Init["ScriptOptions\n(System Refs + NuGet Refs + Usings)"]
        S0["Submission #0: ScriptState\n(Creates 'm' field, Output = 10)"]
        S1["Submission #1: ScriptState.ContinueWithAsync\n(References S0, Reads 'm', Output = 20)"]
        S2["Submission #2: ScriptState.ContinueWithAsync\n(References S1, Rich Media Display)"]
        VarExp["Variable Inspector State\n[m : int = 10]"]
    end

    subgraph Rich Cell Output
        Out1["Text Output / Badge"]
        Out2["Console Output: 20"]
        Out3["Avalonia Image Control\n(Zoom, Copy, Save PNG)"]
    end

    C1 -->|"Execute Cell"| S0
    S0 -->|"State Chaining"| S1
    C2 -->|"Execute Cell"| S1
    S1 -->|"State Chaining"| S2
    C3 -->|"Execute Cell"| S2
    
    S0 --> VarExp
    S1 --> VarExp
    S2 --> VarExp

    S0 --> Out1
    S1 --> Out2
    S2 --> Out3

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📜 License

MIT License. See LICENSE for details.