GridForge

Next-Generation Native macOS Spreadsheet Engine
Real formula engine, XLSX import/export, premium UI. Built with Swift + SwiftUI.

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Screenshots

Spreadsheet with XLSX Data

Product data imported from .xlsx — formulas, multi-sheet tabs, toolbar, formula bar, status bar

Formula Bar & Cell Selection

Formula bar shows cell content — name box displays address, f(x) indicator, raw formula/value

Inspector Panel

Side inspector with Cell Info, Font & Text formatting, Colors, and Sheet Info sections

Range Selection with Statistics

Multi-cell selection with live statistics in the status bar (Sum, Average, Count)

Dark Mode

Full dark mode support — adaptive system colors throughout the entire interface

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What is GridForge?

GridForge is a serious, native macOS spreadsheet application built from scratch in Swift + SwiftUI — without Xcode. It features a real formula engine with 50+ functions, genuine XLSX import/export compatible with Excel, a high-performance virtualized grid, and a premium modern UI.

This is not a demo or prototype. GridForge is a production-grade spreadsheet foundation with:

• A complete tokenizer + recursive descent parser + AST evaluator formula engine
• Real OpenXML (.xlsx) reader/writer with roundtrip fidelity
• A virtualized grid renderer using Core Graphics with cached offsets and binary search
• Full dark mode support with adaptive system colors
• Command-pattern undo/redo with batch operations
• Apple Developer ID signed and notarized for Gatekeeper-clean distribution

XLSX Compatibility Promise

GridForge's XLSX promise is: Open existing Excel files safely and preserve unsupported workbook content.

The XLSX layer now carries the original package parts through the workbook model and overlays GridForge-owned workbook, worksheet, and shared-string parts on save. This is a preservation baseline, not a claim that every OpenXML feature is editable yet.

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Download

Artifact	Size	Details
GridForge.dmg	2.4 MB	Signed & Notarized. Drag to Applications.

Requires macOS 14 (Sonoma) or later. Universal binary (Apple Silicon + Intel).

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Feature Matrix

Spreadsheet Core

Feature	Status	Details
Multi-sheet workbooks	Done	Add, delete, rename, duplicate, reorder
Cell editing	Done	Inline + formula bar editing
Formula engine	Done	50+ functions, recursive descent parser, dependency graph
Cell references	Done	A1-style, absolute ($A$1), cross-cell
Range references	Done	A1:B10 ranges in formulas
Dependency tracking	Done	Directed graph with topological sort
Circular reference detection	Done	Cycle detection with #CIRCULAR! error
Recalculation engine	Done	Full + incremental (affected cells only)
XLSX import	Done	OpenXML reader via ZIPFoundation
XLSX export	Done	Excel-compatible output
CSV export	Done	With proper escaping
Undo / Redo	Done	Command pattern, batch support
Copy / Cut / Paste	Done	Tab-separated, multi-cell, clipboard
Row/Column insert/delete	Done	With undo support
Column resize	Done	Drag column header borders
Selection	Done	Single, range, shift-extend, keyboard
Keyboard navigation	Done	Arrows, Tab, Enter, Home, End, Page Up/Down

Formula Functions (50+)

Category	Functions
Math	SUM, AVERAGE, MIN, MAX, COUNT, COUNTA, ABS, ROUND, INT, MOD, POWER, SQRT, CEILING, FLOOR, LOG, LN, EXP, TRUNC
Logical	IF, AND, OR, NOT, IFERROR, IFNA
Lookup	VLOOKUP, INDEX, MATCH
Conditional	SUMIF, COUNTIF
Text	LEN, LEFT, RIGHT, MID, UPPER, LOWER, TRIM, CONCATENATE, FIND, SUBSTITUTE, TEXT
Info	ISBLANK, ISNUMBER, ISTEXT, ISERROR, TYPE
Date	TODAY, NOW
Operators	+ - * / ^ % & = <> < > <= >=

UI & UX

Feature	Status	Details
Native macOS UI	Done	SwiftUI + AppKit hybrid
Dark mode	Done	Full adaptive colors via system semantics
Formula bar	Done	Name box + formula editor
Sheet tabs	Done	Capsule tabs, context menu, hover states
Side inspector	Done	Cell info, formatting, sheet stats
Status bar	Done	Selection stats (Sum, Average, Count)
Toolbar	Done	File, Format, Edit, View actions
Context menu	Done	Right-click Cut/Copy/Paste, Insert/Delete
Hover feedback	Done	Cell + header highlighting
Column resize	Done	Drag header borders
Error banner	Done	Auto-dismiss error notifications
Dirty tracking	Done	Window title shows unsaved state
Open/Save panels	Done	Native macOS panels, unsaved changes warning

Keyboard Shortcuts

Shortcut	Action
Cmd+N	New workbook
Cmd+O	Open XLSX
Cmd+S	Save
Cmd+Shift+S	Save As
Cmd+Shift+E	Export CSV
Cmd+Z	Undo
Cmd+Shift+Z	Redo
Cmd+X/C/V	Cut / Copy / Paste
Cmd+A	Select all
Cmd+B/I/U	Bold / Italic / Underline
Cmd+=/-/0	Zoom in / out / reset
F2	Edit cell
Enter	Commit + move down
Tab	Commit + move right
Escape	Cancel edit
Delete	Clear cell(s)
Arrow keys	Navigate
Shift+Arrow	Extend selection
Page Up/Down	Scroll viewport
Home/End	First / last column
Cmd+Home	Go to A1

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Architecture

GridForge is built as 5 decoupled engines:

┌─────────────────────────────────────────────────┐
│                   GridForge.app                  │
│  ┌─────────────────────────────────────────────┐ │
│  │              UI Layer (SwiftUI)              │ │
│  │  Toolbar │ FormulaBar │ Grid │ Tabs │ Inspector │
│  └──────────────────┬──────────────────────────┘ │
│  ┌──────────────────┴──────────────────────────┐ │
│  │           WorkbookViewModel                  │ │
│  │    State coordination + command dispatch     │ │
│  └──────┬────────┬────────┬────────┬───────────┘ │
│  ┌──────┴──┐ ┌───┴───┐ ┌──┴──┐ ┌──┴──┐ ┌──────┐ │
│  │Workbook │ │Formula│ │XLSX │ │Undo │ │Select│ │
│  │ Engine  │ │Engine │ │R/W  │ │Redo │ │Model │ │
│  └─────────┘ └───────┘ └─────┘ └─────┘ └──────┘ │
└─────────────────────────────────────────────────┘

Module Breakdown

Module	Path	LOC	Purpose
Workbook	Sources/GridForgeCore/Workbook/	675	Data model: Cell, Worksheet, Workbook, CellAddress, CellValue
Formula Engine	Sources/GridForgeCore/FormulaEngine/	2,167	Tokenizer, Parser, AST, Evaluator, DependencyGraph
XLSX Engine	Sources/GridForgeCore/ImportExport/	802	OpenXML reader/writer via ZIPFoundation
Infrastructure	Sources/GridForgeCore/{Selection,UndoRedo,Grid}/	624	Selection state, command-pattern undo, viewport model
UI	Sources/GridForge/	2,644	Grid renderer, formula bar, tabs, inspector, theme
Tests	Tests/GridForgeTests/	721	Model, formula, XLSX roundtrip tests

Formula Engine Internals

Input: "=SUM(A1:A10)*2+1"
         │
    ┌────▼────┐
    │Tokenizer│  → [FUNC("SUM"), LPAREN, REF("A1"), COLON, REF("A10"), RPAREN, MULT, NUM(2), PLUS, NUM(1)]
    └────┬────┘
    ┌────▼────┐
    │ Parser  │  → BinaryOp(+, BinaryOp(*, FunctionCall("SUM", [Range(A1,A10)]), Num(2)), Num(1))
    └────┬────┘
    ┌────▼─────┐
    │Evaluator │  → Resolve refs → Evaluate AST → .number(result)
    └────┬─────┘
    ┌────▼──────────┐
    │DependencyGraph│  → Track A1→A10 precedents, trigger recalc on change
    └───────────────┘

Grid Rendering Pipeline

The grid uses NSView + Core Graphics (not SwiftUI views) for performance:

• Cached cumulative offsets: O(1) position lookups via precomputed arrays
• Binary search: O(log n) hit-testing for column/row at point
• Batched drawing: All vertical lines in one stroke, then all horizontal
• Cached font attributes: 4 font variants (normal, bold, italic, bold+italic) created once
• Dirty rect clipping: Only redraws the invalidated region

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Build from Source

# Clone
git clone https://github.com/Worth-Doing/GridForge.git
cd GridForge

# Build (release + app bundle)
./build.sh build

# Run
open GridForge.app

# Run tests
./build.sh test

# Create signed DMG
./build.sh dmg

# Notarize with Apple
./build.sh notarize

Requirements

• macOS 14+
• Swift 5.9+
• No Xcode project required — built entirely with Swift Package Manager

Build Commands

Command	Description
./build.sh build	Release build + .app bundle with icon
./build.sh run	Debug build + launch
./build.sh test	Run 64 unit tests
./build.sh dmg	Build + code sign + create DMG
./build.sh notarize	Submit to Apple notarization + staple
./build.sh clean	Remove all build artifacts

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Project Structure

GridForge/
├── Package.swift
├── build.sh
├── Assets/
│   ├── GridForge-Logo.svg
│   └── GridForge.icns
├── Sources/
│   ├── GridForgeCore/           # Core engine library
│   │   ├── Workbook/            # Cell, Worksheet, Workbook models
│   │   ├── FormulaEngine/       # Tokenizer, Parser, Evaluator, DependencyGraph
│   │   ├── ImportExport/        # XLSX Reader & Writer
│   │   ├── Selection/           # Selection state machine
│   │   ├── UndoRedo/            # Command-pattern undo/redo
│   │   └── Grid/                # Viewport model
│   └── GridForge/               # App + UI
│       ├── App/                 # @main entry, menus
│       ├── DesignSystem/        # Colors, typography, spacing, animations
│       ├── Features/            # ViewModel, window layout
│       └── UI/                  # GridView, FormulaBar, SheetTabs, Inspector
└── Tests/
    └── GridForgeTests/          # Model, Formula, XLSX tests

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Testing

64 tests, 0 failures

FormulaTests (30):   Arithmetic, precedence, cell refs, functions, comparisons, recalculation, dependency graph
ModelTests (22):     CellAddress parsing, ranges, worksheet CRUD, workbook management, selection
XLSXTests (12):      Export, roundtrip strings/numbers/booleans/formulas/special chars, large sheets

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Tech Stack

Component	Technology
Language	Swift 5.9+
UI Framework	SwiftUI + AppKit (NSViewRepresentable)
Grid Rendering	Core Graphics (NSView + CGContext)
Build System	Swift Package Manager (CLI)
XLSX Parser	ZIPFoundation + Foundation XMLParser
Formula Engine	Custom tokenizer + recursive descent parser
Architecture	MVVM + Command Pattern
Code Signing	Developer ID Application
Notarization	Apple Notary Service

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Roadmap

V2 — Power Features

• Cell formatting in XLSX export (colors, bold, borders)
• Frozen panes (freeze top rows / left columns)
• Advanced filtering & sorting UI
• Conditional formatting rules
• Column/row auto-fit
• 100+ additional formula functions

V3 — Advanced System

• Charts & data visualization
• Pivot tables
• Scripting layer
• Plugin system
• External data source connectors

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License

MIT License. See LICENSE for details.

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_{Built with Swift + SwiftUI by WorthDoing AI}