Code Style

Swift conventions, tooling, naming, and file organization rules

Code Style

Tools

.swiftlint.yml and .swiftformat are the source of truth. When in doubt, check those files.

# Check for issues
swiftlint lint

# Auto-fix
swiftlint --fix

# Format all code
swiftformat .

# Check formatting without applying
swiftformat --lint .

SwiftLint also runs during Xcode builds automatically.

Formatting

Rule	Value
Indentation	4 spaces (never tabs)
Line length	120 chars (SwiftLint warns at 180, errors at 300)
Braces	K&R (opening brace on same line)
Line endings	LF
Semicolons	None
Trailing commas	None

Naming

Element	Convention	Example
Classes, Structs, Enums, Protocols	UpperCamelCase	DatabaseConnection
Enum cases	lowerCamelCase	.postgresql
Functions, Variables, Constants	lowerCamelCase	executeQuery(), maxRetryAttempts
Booleans	is/has/can prefix	isConnected, hasValidCredentials
Factory methods	make prefix	makeConnection()
Acronyms	Treat as words	JsonEncoder not JSONEncoder (except SDK types)

Access Control

Always explicit. Prefer the most restrictive level that works.

// Specify on the extension, not individual members
public extension NSEvent {
    var semanticKeyCode: KeyCode? { ... }
}

Imports

System frameworks first (alphabetical), then third-party, then local. Blank line after imports.

import AppKit
import Foundation
import os

import CodeEditSourceEditor

import TableProPluginKit

Safety

No force unwrapping (!) or force casting (as!). Use guard let, if let, as?.

// Good
guard let connection = activeConnection else { return }

// Bad
let connection = activeConnection!

Logging

OSLog only. Never print().

import os

private static let logger = Logger(subsystem: "com.TablePro", category: "DatabaseManager")

Localization

• String(localized:) for user-facing strings in computed properties, AppKit code, alerts, error descriptions
• SwiftUI view literals (Text("Save"), Button("Cancel")) auto-localize
• Do not localize technical terms: font names, database types, SQL keywords, encoding names
• Never use String(localized:) with string interpolation. Use String(format: String(localized: "Preview %@"), name) instead.

SwiftUI Patterns

• @State for local view state
• @Observable for viewmodels (Swift 5.9+)
• Property wrapper order: Environment, State, Binding, regular properties
• Extract large views into subviews

Limits

Metric	Warning	Error
File length	1200 lines	1800 lines
Type body	1100 lines	1500 lines
Function body	160 lines	250 lines
Cyclomatic complexity	40	60

When approaching these limits, extract into extension files:

MainContentCoordinator.swift

Extensions

MainContentCoordinator+RowOperations.swift

MainContentCoordinator+Pagination.swift

MainContentCoordinator+Filtering.swift

Group by domain logic, not arbitrary line counts.