haskell-debugginglisted

# Haskell Debugging Two complementary approaches: the **GHCi built-in debugger** (fast, terminal-based, no setup beyond GHCi) and **DAP adapters** (integrated into VS Code and other editors with a GUI). ## GHCi debugger The GHCi debugger is always available — no extra packages. Load your module with `cabal repl` or `ghci`, then use these commands: ### Setting breakpoints ``` -- By function name :break MyModule.myFunction -- By module and line number :break MyModule 42 -- List active breakpoints :show breaks -- Delete a breakpoint by index (from :show breaks output) :delete 0 ``` ### Stepping through execution ``` -- Run until next breakpoint; starts evaluation :continue -- Step into the next redex (one reduction) :step -- Step over (run to next line without entering calls) :steplocal -- Step to next breakpoint in a specific module :stepmodule MyModule ``` ### Inspecting state at a breakpoint ``` -- Print a variable (forces evaluation) :print x -- Force a thunk and print (like :print but evaluates completely) :force x -- Show current locals in scope :show bindings -- Evaluate an expression in the current context x + 1 ``` ### Tracing (non-interactive) When you don't want to step but want a call history: ``` -- Run with tracing enabled; builds a call history :trace myFunction arg1 -- Show the call history after a breakpoint or exception :history -- Show the back trace :back ``` ### Catching exceptions ``` -- Break on any exception :set -fbreak-on-except