Rust EXEL

A Professional, Native, Cross-Platform Spreadsheet, Formula Engine & Workbook Editor Built with Rust

Features • Architecture • Quickstart • File Formats • Contributing • License

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📖 Overview

Rust EXEL is an independent, native desktop spreadsheet application inspired by Microsoft Excel, engineered from the ground up in pure Rust. It delivers native performance, actual calculation semantics, and hardware-accelerated rendering through egui and wgpu (with automatic glow fallback) without web wrappers, Electron, or simulated grids.

Whether you're opening massive 100,000+ row datasets, computing complex nested formulas with cross-sheet dependencies, formatting tables, or exporting to Microsoft Excel-compatible .xlsx, Rust EXEL is designed for speed, safety, and productivity.

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⚡ Key Highlights

• 🚀 Full Excel Scale (1M+ Rows): Sparse matrix cell store supporting standard Excel limits (1,048,576 rows × 16,384 columns / A through XFD) without eager RAM allocation.
• 🎨 Hardware-Accelerated Virtual Grid: Custom egui::Painter engine that renders strictly visible rows and columns for silky smooth 60+ FPS navigation. Automatic fallback from Wgpu to Glow OpenGL ensures compatibility across all GPUs and virtual machines.
• 🧮 True Formula Recalculation Engine:
  • Directed Acyclic Graph (DAG) dependency tracking with Kahn's topological sort.
  • Automatic cycle detection powered by Tarjan's Strongly Connected Components algorithm (flags cycles with #CIRCULAR!).
  • Standard Excel functions: SUM, PRODUCT, AVERAGE, COUNT, COUNTA, IF, AND, OR, NOT, IFERROR, VLOOKUP, INDEX, MATCH, CONCAT, LEFT, RIGHT, MID, LEN, MOD, SQRT, ROUND, and more.
  • Full propagation of error types (#DIV/0!, #VALUE!, #REF!, #NAME?, #N/A, #NUM!).
• 📂 High-Fidelity File Compatibility:
  • XLSX: Native read & write support preserving values, formulas, fonts, fills, borders, alignments, and column widths.
  • CSV / TSV / JSON: Fast import and export with delimiter sniffing and automatic data-type inference.
  • Atomic File Saving: Secure replacement via tempfile so save operations never corrupt existing files.
  • Macro Safety: Automatically detects and quarantines VBA macros in .xlsm files without ever executing untrusted code.
• 📋 Seamless Clipboard Integration: RFC 4180-compliant TSV clipboard formatting and parsing (exel-clipboard) with system clipboard synchronization via arboard, allowing seamless copy/paste between Rust EXEL, Microsoft Excel, and Google Sheets.
• ⌨️ Keyboard-First Excel Workflow: Complete shortcut registry supporting Windows, Linux, and macOS (F2 inline edit, F4 cycle absolute references $A$1 / A$1 / $A1, Alt+= AutoSum, Ctrl+Z / Ctrl+Y undo/redo, Ctrl+Arrows region jump).
• 🖥️ Full Desktop Ribbon UI: 10 functional ribbon tabs (File, Home, Insert, Page Layout, Formulas, Data, Review, View, Developer, Help), Name Box with cell jumping, multiline expandable Formula Bar, and bottom sheet tabs with live selection statistics (Average, Count, Sum).
• 🛡️ Startup & Error Resilience: Automatic graphics renderer fallback (wgpu -> glow), diagnostic crash logging to crash.log, and safe image buffer validation.

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🏗️ Workspace Architecture

The project is structured as a modular Cargo workspace with 25 independent crates and applications:

rust-exel/
├── apps/
│   ├── rust-exel/              # Native GUI desktop application (eframe + wgpu / glow fallback)
│   └── rust-exel-cli/          # Headless spreadsheet calculation, evaluation & batch conversion CLI
├── crates/
│   ├── exel-core/              # Coordinate models (CellCoord, CellRange, SheetId, A1 conversions)
│   ├── exel-cell/              # SparseCellStore, CellValue, CellState, and CellError models
│   ├── exel-workbook/          # Multi-sheet Workbook, Worksheet, dimensions, named ranges
│   ├── exel-dependency-graph/  # Directed graph, cycle detection, topological sorter
│   ├── exel-formula/           # Lexer, AST parser, cross-sheet reference resolution
│   ├── exel-calc/              # Formula evaluator, function registry, recalculation engine
│   ├── exel-formatting/        # Fonts, fills, borders, alignments, number format codes
│   ├── exel-commands/          # Concrete undoable commands (SetCell, InsertRow, DeleteCol, etc.)
│   ├── exel-history/           # Bounded history stack with transaction support
│   ├── exel-tables/            # Structured tables, table styles, structured references
│   ├── exel-validation/        # Data validation criteria (whole number, decimal, list, date, text length)
│   ├── exel-clipboard/         # RFC-compliant TSV serialization/parsing & system clipboard integration
│   ├── exel-io/                # Generic I/O traits, format sniffing, and atomic file persistence
│   ├── exel-csv/               # CSV, TSV, and JSON importers and exporters
│   ├── exel-xlsx/              # High-fidelity XLSX read/write adapter (calamine & rust_xlsxwriter)
│   ├── exel-shortcuts/         # Central cross-platform ShortcutRegistry (Windows, Linux, macOS)
│   ├── exel-charts/            # Chart configurations, series extraction, visual styles
│   ├── exel-pivot/             # Multi-dimensional pivot table aggregation engine
│   ├── exel-data/              # Data analysis tools, sorting, quick filters, transformations
│   ├── exel-print/             # Page setup, paper sizes, print area, and ASCII/PDF print preview
│   ├── exel-automation/        # Batch scriptable automation runner (JSON scripts)
│   └── exel-ui/                # Virtualized grid, Ribbon, Formula Bar, Sheet tabs, Format dialog
└── assets/
    └── icons/                  # Application icons and branding assets

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🚀 Quickstart

Prerequisites

• Rust Stable (1.85.0 or later)

Build & Run Desktop App

# Clone the repository
git clone https://github.com/Sami12901/RustEXCEL.git
cd RustEXCEL

# Run the native desktop application
cargo run --bin rust-exel

# Run in optimized release mode
cargo run --release --bin rust-exel

Run Tests

# Run all 295 unit and integration tests across the workspace
cargo test --workspace

Headless CLI Tool

# Evaluate a formula
cargo run --bin rust-exel-cli -- eval "SUM(10, 20, 30) * 2"

# Convert XLSX to CSV
cargo run --bin rust-exel-cli -- convert input.xlsx output.csv

# Inspect sheet info
cargo run --bin rust-exel-cli -- info workbook.xlsx

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🛡️ Security & Untrusted File Safety

1. No Macro Execution: Embedded VBA code in XLSM files is quarantined and never executed.
2. Safe Atomic Persistence: Files are written to temporary storage and validated before replacing the destination file.
3. Memory Safety: Pure Rust implementation guarantees zero buffer overflows or dangling pointers.

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📄 License

Dual-licensed under either:

• MIT License (LICENSE or http://opensource.org/licenses/MIT)
• Apache License, Version 2.0 (http://www.apache.org/licenses/LICENSE-2.0)

at your option.

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Crafted with ❤️ in Rust