GoSheet

A powerful terminal-based spreadsheet application built with Go

Features • Installation • Usage • Functions • File Formats • Contributing

📋 Overview

GoSheet is a feature-rich, lightweight spreadsheet application that runs entirely in your terminal. Built with Go and powered by tview, it offers a modern alternative to traditional spreadsheet software with an emphasis on performance, simplicity, and powerful formula capabilities.

Why GoSheet?

🚀 Fast & Lightweight: Minimal resource usage with optimized viewport rendering
💻 Terminal-Native: No GUI overhead, works anywhere with a terminal
🔧 Powerful Formulas: 104+ built-in functions for complex calculations
📊 Multiple Sheets: Full workbook support with unlimited sheets
🎨 Rich Formatting: Colors, alignment, text effects, and more
💾 Multiple Formats: Native .gsheet, JSON, Excel (.xlsx), CSV, HTML, and TXT support
⚡ Excel-Like Features: Data validation, sorting, find/replace, and autofill

✨ Features

Core Spreadsheet Features

📊 Workbook Management: Create, rename, duplicate, and reorder sheets
🔢 Formula Engine: 104 built-in functions with circular dependency detection
🎨 Cell Formatting: Bold, italic, underline, strikethrough, colors, alignment
📐 Data Types: String, Number, Financial, DateTime with automatic detection
✅ Data Validation: Excel-like validation rules with custom error messages
📝 Cell Comments: Add notes and annotations to any cell
🔍 Find & Replace: Search with case-sensitive and whole-word options
📋 Clipboard Operations: Cut, copy, paste with format painter
↩️ Undo/Redo: Full history management per sheet
🔄 AutoFill: Smart pattern detection for dates, numbers, and sequences

Advanced Features

🎯 Smart Navigation: Go-to-cell, keyboard shortcuts, multi-sheet switching
📊 Sorting: Ascending/descending sort with type-aware comparison
🔐 Cell Protection: Mark cells as editable/non-editable
🎨 Format Painter: Copy and paste cell formatting
📏 Custom Cell Sizes: Adjustable min/max widths per cell
🔢 Number Formatting: Customizable thousands/decimal separators, decimal places
💰 Financial Formatting: Currency symbols with full formatting control
📅 Date/Time Support: Multiple format options with auto-detection
🚀 Viewport Optimization: Renders only visible cells for maximum performance
📦 Excel Import/Export: Full .xlsx support with formulas, formatting, and colors

🚀 Installation

Prerequisites

Go 1.24.2 or higher
Terminal with 256-color support (recommended)

From Source

# Clone the repository
git clone https://github.com/drclcomputers/gosheet.git
cd gosheet

# Build the application
go build -o gosheet

# Run GoSheet
./gosheet

Quick Start

# Create a new spreadsheet
./gosheet

# Open an existing file
./gosheet -file path/to/workbook.gsheet

# Open from start menu
./gosheet
# Then select file from recent files or browse

📖 Usage

Basic Navigation

Note: For MacOS users, activating 'Use Option as Meta Key' is mandatory for Alt commands to work. Here is a link "https://superuser.com/questions/1038947/using-the-option-key-properly-on-mac-terminal" for more info.

Key Combination	Action
Arrow Keys	Navigate cells
Shift + Arrows	Select range
Enter	Edit selected cell
Escape	Save menu / Exit dialog
Alt + G	Go to cell

Editing & Clipboard

Key Combination	Action
Alt + C	Copy selection
Alt + V	Paste
Alt + X	Cut
Alt + Delete	Clear cells
Alt + Z	Undo
Alt + Y	Redo

Formatting

Key Combination	Action
Alt + R	Copy cell format
Alt + I	Paste cell format
Alt + N	Edit cell comment

Sheet Management

Key Combination	Action
Alt + M	Open Sheet Manager
Alt + T	Quick Sheet Menu
Alt + PageUp	Previous sheet
Alt + PageDown	Next sheet
Alt + 1-9	Quick switch to sheet

Advanced Operations

Key Combination	Action
Alt + O	Sort dialog
Alt + A	AutoFill
Alt + F	Find
Alt + H	Replace
F3 / F4	Find previous/next
Alt + =	Insert row/column
Alt + -	Delete row/column
Alt + /	Show help

🧮 Functions

GoSheet includes 104 built-in functions organized into 22 categories:

Mathematical Functions (31)

Trigonometric (4)

SIN, COS, TAN, CTAN

Inverse Trigonometric (5)

ASIN, ACOS, ATAN, ATAN2, ACTAN

Additional Trigonometric (4)

SEC, CSEC, ASEC, ACSC

Degrees/Radians (2)

RAD, DEG

Hyperbolic (4)

SINH, COSH, TANH, CTANH

Additional Hyperbolic (8)

SECH, CSCH, ASINH, ACOSH, ATANH, ASECH, ACSCH, ACOTH

Exponential/Logarithmic (4)

EXP, LOG, LOG10, LOG2

Power & Basic Math (13)

Power/Roots (3)

SQRT, CBRT, POW

Basic Math (7)

ABS, CEIL, FLOOR, ROUND, MIN, MAX, AVG

Utility Math (3)

SIGN, CLAMP, LERP

Logical Functions (6)

IF, IFS, AND, OR, NOT, XOR

String Functions (11)

LEFT, RIGHT, MID, UPPER, LOWER, PROPER, TRIM, FIND, SUBSTITUTE, LEN, CONCAT

Date/Time Functions (13)

NOW, TODAY, DATE, TIME, YEAR, MONTH, DAY, HOUR, MINUTE, SECOND, WEEKDAY, DATEDIFF, DATEADD

Type Checking (4)

CHOOSE, ISNUMBER, ISTEXT, ISBLANK

Statistical (3)

COUNT, SUM, PRODUCT

Constants (5)

PI, E, PHI, INF, NAN

Special Math (6)

ERF, ERFC, GAMMA, J0, J1, YN

Rounding/Precision (2)

TRUNC, ROUNDTO

Engineering (3)

HYPOT, MOD, REMAINDER

Bitwise Operations (5)

BITAND, BITOR, BITXOR, BITSHIFTLEFT, BITSHIFTRIGHT

Additional Math Utility (3)

FACTORIAL, GCD, LCM

Formula Examples

# Basic arithmetic
$= 10 + 20 * 3

# Cell references
$= A1 + B2

# Functions
$= SUM(A1, B1, C1)
$= IF(A1 > 100, "High", "Low")
$= AVERAGE(A1, A2, A3, A4, A5)

# Nested functions
$= ROUND(AVG(A1, A2, A3), 2)

# Date calculations
$= DATEDIFF(TODAY(), "2024-01-01")

# String manipulation
$= CONCAT(UPPER(A1), " - ", LOWER(B1))

# Complex formulas
$= IF(SUM(A1, A2) > 100, MAX(B1, B2), MIN(C1, C2))

# Cell ranges
$=SUM(A1:A10)           // Single column range
$=SUM(A1:C1)            // Single row range
$=SUM(A1:C10)           // Multi-cell range
$=AVG(B2:B20)           // Works with any function
$=MAX(A1:A5, C1:C5)     // Multiple ranges
$=SUM(A1:A10) + AVG(B1:B10)  // Ranges in expressions

Cell A1: 10
Cell A2: 20
Cell A3: 30
Cell B1: $=SUM(A1:A3)   → Result: 60

Cell C1: 5
Cell C2: 15
Cell C3: 25
Cell D1: $=AVG(A1:A3, C1:C3)  → Result: 17.5

📁 File Formats

Supported Formats

Format	Extension	Read	Write	Description
GSheet	`.gsheet`	✅	✅	Native format (gzipped JSON)
JSON	`.json`	✅	✅	Human-readable JSON
Excel	`.xlsx`	✅	✅	Microsoft Excel format
CSV	`.csv`	❌	✅	Comma-separated values
TXT	`.txt`	✅	✅	Tab-delimited text
HTML	`.html`	❌	✅	Styled HTML table

Excel Support Notes

GoSheet provides comprehensive Excel import/export capabilities with the following features:

Import Features:

✅ Multiple sheets with names preserved
✅ Cell values and formulas (auto-evaluated on load)
✅ Text formatting: bold, italic, underline, strikethrough
✅ Font colors (RGB/hex)
✅ Background colors (including empty cells with formatting)
✅ Text alignment (left, center, right)
✅ Cell comments and notes
✅ Number formats with decimal places
✅ Column widths
⚠️Complex Excel-specific formulas may need adjustment
❌ Charts, images, pivot tables, macros not supported

Export Features:

✅ All sheets with original names
✅ Formulas (converted to Excel format)
✅ All cell formatting preserved
✅ Font and background colors
✅ Comments and notes
✅ Number formatting
✅ Column widths
✅ Text alignment

Known Excel Compatibility Notes

The @ Symbol Issue When opening GoSheet-exported Excel files in newer versions of Excel (2019/365), you may see an @ symbol automatically inserted before some formulas:

# Original formula in GoSheet
$=SUM(A1:A10)

# How Excel 2019+ may display it
=@SUM(A1:A10)

This is normal Excel behavior, not a bug in GoSheet. The @ is Excel's "implicit intersection operator" and doesn't affect functionality. Excel adds it automatically when loading the file. Users can manually remove it if desired, but it's not necessary.

Formula Conversion

Most common functions work identically (SUM, AVG, IF, MAX, MIN, COUNT, etc.)
GoSheet formulas use $= prefix; this is automatically stripped for Excel export
Some advanced GoSheet-specific functions may not have Excel equivalents
Cell ranges (A1:A10) are fully compatible

Tips for Best Compatibility

Use standard functions: Stick to common functions like SUM, AVG, IF, MAX, MIN for maximum compatibility
Test formulas: Always verify complex formulas work in Excel after export
Colors: RGB colors are fully supported and preserved
Formatting: Bold, italic, underline, and alignment are 100% compatible
Save as .gsheet: Use native format for full feature preservation

🔧 Configuration

Terminal Requirements

Minimum: 80x24 characters
Recommended: 120x40 or larger
Colors: 256-color support recommended
Fonts: Monospace font required

Memory Usage

GoSheet uses an optimized viewport system that renders only visible cells:

Base Memory: ~5-10 MB
Per 10,000 Cells: ~2-5 MB additional
Viewport Cleanup: Automatically frees unused cell memory

Performance Tips

Viewport Size: Larger terminals show more cells but use more memory
Formula Optimization: Avoid deeply nested formulas when possible
Data Cleanup: Delete unused sheets and cells periodically
File Format: Use .gsheet for best performance

🎨 Data Validation

GoSheet includes Excel-like data validation with 14 preset types:

Validation Presets

Whole Number - Between: Value must be integer in range
Whole Number - Greater Than: Integer greater than value
Whole Number - Less Than: Integer less than value
Decimal - Between: Float in range
Decimal - Greater Than: Float greater than value
Decimal - Less Than: Float less than value
Text Length - Between: String length in range
Text Length - Maximum: String length limit
Text - Not Empty: Required field
List - Allowed Values: Dropdown-like validation
Email Format: Basic email validation
Positive Numbers Only: Must be > 0
Percentage (0-100): Value between 0 and 100
Custom: Write your own validation expression

Custom Validation Examples

# Value must be even
THIS % 2 == 0

# Value must be between 0 and 100
THIS >= 0 && THIS <= 100

# Text must start with "ID-"
FIND("ID-", THIS) == 1

# Must be valid email format
CONTAINS(THIS, "@") && CONTAINS(THIS, ".")

🏗️ Architecture

Project Structure

gosheet/
├── internal/
│   ├── services/
│   │   ├── cell/              # Cell data structures and operations
│   │   ├── fileop/            # File I/O operations and format handlers
│   │   ├── table/             # Table management, sheets, forumula engine and viewport
│   │   └── ui/                # User interface components
│   │       ├── cell/              # Cell editing and formatting UI
│   │       ├── datavalidation/    # Validation rules and dialogs
│   │       ├── file/              # File browser and start menu
│   │       ├── navigation/        # Find, replace, and go-to dialogs
│   │       └── sheetmanager/      # Sheet management UI
│   └── utils/                 # Utility functions
│       └── evaluatefuncs/         # Formula evaluation functions
├── demo_imgs/                 # Demo screenshots and GIFs
├── go.mod
├── go.sum
├── LICENSE.md
├── README.md
└── main.go

Key Components

Cell Service: Manages individual cell data, formatting, and formulas
File Service: Format-agnostic file operations with pluggable handlers (.gsheet, .xlsx, .json, etc.)
Table Service: Viewport management, sheet operations, undo/redo, and memory optimization
UI Service: Dialogs, menus, and user interactions
Formula Engine: Expression evaluation engine with 104 built-in functions and circular dependency detection
Utils: Helper functions for colors, date/time, formatting, and column naming

🤝 Contributing

Contributions are welcome! Here's how you can help make GoSheet better:

Ways to Contribute

🐛 Report bugs and issues
💡 Suggest new features
📖 Improve documentation
🔧 Submit bug fixes
✨ Add new features
🧪 Write tests

Reporting Issues

When reporting issues, please include:

GoSheet version (visible in start menu)
Operating system and terminal emulator
Steps to reproduce the issue
Expected vs actual behavior
Screenshots if applicable

Pull Requests

Fork the repository
Create a feature branch: git checkout -b feature/amazing-feature
Make your changes with clear, atomic commits
Add tests for new functionality
Update documentation (README, code comments)
Ensure code follows Go conventions
Test thoroughly on your platform
Push to your fork: git push origin feature/amazing-feature
Open a Pull Request with clear description

Development Guidelines

Code Style: Follow standard Go formatting (gofmt, golint)
Comments: Add clear comments for complex logic
Testing: Include unit tests for new functions
Documentation: Update README for user-facing changes
Commits: Write descriptive commit messages

Areas for Contribution

Some areas where contributions would be especially valuable:

📊 Chart and graphing support
🎨 Conditional formatting
📈 Pivot table functionality
🔌 Plugin system architecture
📄 Additional export formats (PDF, ODS)

📄 License

This project is licensed under the MIT License - see the LICENSE.md file for details.

MIT License

Copyright (c) 2025 drclcomputers

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.

🙏 Acknowledgments

Dependencies

tview - Terminal UI framework
tcell - Terminal handling
expr - Expression evaluation
excelize - Excel file format library
golang.org/x/term - Terminal utilities
golang.org/x/text - Text processing

Inspiration

GoSheet was inspired by:

VisiCalc (1979) - The original spreadsheet program
Lotus 1-2-3 (1983) - Revolutionary spreadsheet software
sc - Classic terminal spreadsheet calculator and its succesor sc-im
Microsoft Excel - Modern spreadsheet features and UX
LibreOffice Calc - Open-source spreadsheet alternative
Google Sheets - Cloud-based collaboration features

📊 Project Stats

Lines of Code: ~15,000+
Functions: 104 built-in
File Formats: 6 supported
Go Version: 1.24.2
Started: October 2025
Status: Active Development
License: MIT

🗺️ Roadmap

💬 Support

Issues: GitHub Issues
Discussions: GitHub Discussions

🌟 Star History

If you find GoSheet useful, please consider giving it a star on GitHub!

Built with ❤️ using Go

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Name		Name	Last commit message	Last commit date
Latest commit History 16 Commits
demo_imgs		demo_imgs
internal		internal
.gitignore		.gitignore
LICENSE.md		LICENSE.md
README.md		README.md
go.mod		go.mod
go.sum		go.sum
main.go		main.go

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drclcomputers/GoSheet

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