Erlang Debugger vs FLEX

Erlang Debugger is a graphical interface for debugging and testing Erlang programs. Developers can set line, conditional, and function breakpoints, then attach to a process to step, continue, finish, skip, or stop its execution. The Attach Process window displays variable bindings and allows editing values when they can be represented in the running system. A Monitor window shows interpreted modules and information about processes running interpreted code. Debugger can record interpreted function calls for stack navigation, though recording tail calls uses more memory and can slow execution when many tail-recursive calls are involved. Modules need debug information, for example from compilation with `erlc +debug_info`. Global mode can interpret code on known nodes and display their processes, but the documentation warns that using global mode on multiple network nodes can cause interference. The debugger is listed for Linux, macOS, and Windows, and Erlang/OTP releases from version 18.0 onward use the Apache License 2.0. Debugging has runtime tradeoffs: interpreted code runs slower, each debugged process adds a meta process, and timers or tracing may behave differently.

FLEX is a free, open-source debugging and exploration library for iOS applications. It runs inside the app and places a toolbar in a window above it, allowing developers to inspect and change application state without an LLDB or Xcode connection or a remote debugging server. The tool can inspect view hierarchies, find live heap objects, show and modify properties and ivars, and call methods. Its network history covers NSURLConnection and NSURLSession requests with timing, headers, and responses. Developers can browse app bundles and sandboxes, inspect SQLite and Realm databases, and view or edit NSUserDefaults values, including strings, numbers, arrays, and dictionaries. FLEX works in the iOS Simulator and on physical devices, supports Objective-C and Swift, and requires an iOS 9-or-later target. Installation options include CocoaPods, Carthage, Buck, manual Xcode integration, and Swift Package Manager.