Swift helpers, and the lldb setup to use them. Presented @ SLUG https://speakerdeck.com/kastiglione/advanced-debugging-and-swift

helpers.swift

extension UIView {
    /// Example: call someView.nudge(0, 30)
    func nudge(_ dx: CGFloat, _ dy: CGFloat) {
        self.frame = self.frame.offsetBy(dx: dx, dy: dy)
        CATransaction.flush()
    }
}

extension UIView {
    /// Example: po UIView.root
    static var root: UIView {
        return UIApplication.shared.keyWindow!.rootViewController!.view
    }
}

extension UIViewController {
    /// Example: po UIViewController.current
    static var current: UIViewController {
        var controller = UIApplication.shared.keyWindow!.rootViewController!
        if let child = (controller as? UINavigationController)?.topViewController {
            controller = child
        }
        if let container = (controller as? UITabBarController)?.selectedViewController {
            controller = child
        }
        return controller
    }
}

extension UIView {
    /// Example: po UIView.current
    static var current: UIView {
        return UIViewController.current.view
    }
}

extension UIView {
    /// Utility used by others helpers.
    func tree() -> UnfoldSequence<UIView, [UIView]> {
        return sequence(state: [self]) { state in
            guard let view = state.popLast() else { return nil }
            state.append(contentsOf: view.subviews.reversed())
            return view
        }
    }
}

extension UIView {
    func grep(_ pattern: String) -> [UILabel] {
        return self.tree()
            .compactMap { $0 as? UILabel }
            .filter { $0.text?.range(of: pattern) != nil }
    }
}

extension UIView {
    /// Example: po UIButton.first(in: UIView.current)
    static func first(in root: UIView) -> Self? {
        return root.first { _ in true }
    }
    
    /// Example: po UIView.current.first { (b: UIButton) in b.currentTitle == "Tap Me" }
    func first<T: UIView>(where match: (T) -> Bool) -> T? {
        return self.tree()
            .lazy
            .compactMap { $0 as? T }
            .filter(match)
            .first
    }
}

extension UIView {
    func fillText(_ text: String) {
        if let textField = UITextField.first(in: self) {
            textField.text = text
            CATransaction.flush()
        }
    }
}

extension UIView {
    // Example: po someView.screenshot("/some/path.png")
    // Example: shell open /some/path.png
    func screenshot(_ path: String) {
        let renderer = UIGraphicsImageRenderer(bounds: self.bounds)
        let png = renderer.pngData { _ in
            self.drawHierarchy(in: self.bounds, afterScreenUpdates: false)
        }
        do {
            try png.write(to: URL(fileURLWithPath: path))
        } catch let e {
            print("Failed to write \(path): \(e)")
        }
    }
}

// Example: someButton.sendActions(for: $touchUpInside)
let $touchUpInside = UIControl.Event(rawValue: 64)

lldbinit

# create the `alias` used below
command alias alias command alias

# to load python lldb commands
alias import command script import

# to run lldb "shell" scripts
alias source command source

# to run a shell command, like `open`
alias shell platform shell

# tell lldb to assume swift, not objc
settings set target.language swift
alias clear-lang settings clear target.language

# `load_swift` command is used to load helpers written in swift
import ~/load_swift.py

# load_swift path/to/helpers.swift

alias action breakpoint command add
alias autocontinue breakpoint modify --auto-continue true

load_swift.py

import lldb
import os

kNoResult = 0x1001

@lldb.command("load_swift")
def load_swift(debugger, path, ctx, result, _):
    with open(os.path.expanduser(path)) as f:
        contents = f.read()

    options = lldb.SBExpressionOptions()
    options.SetLanguage(lldb.eLanguageTypeSwift)
    error = ctx.frame.EvaluateExpression(contents, options).error

    if error.fail and error.value != kNoResult:
        result.SetError(error)