Features

• The source file extension must be ".hs"
• Can not use STDIN handle while debugging.
• Creating tasks.json.
• Shortcut keys
  • F5 : start / continue debugging
  • F6 : show command menu
  • Shift + F6 : stop watch
  • F7 : clean & build
  • F8 : start test
  • F9 : put a breakpoint on the current line
  • Shift + F9 : put a breakpoint on the current column
  • F10 : step next
  • F11 : step into

Install

Stack

Install haskell-dap, ghci-dap, haskell-debug-adapter at once.

$ stack update
$
$ stack install haskell-dap ghci-dap haskell-debug-adapter
$
$ ghci-dap --version
[DAP][INFO] start ghci-dap-0.0.XX.0.
The Glorious Glasgow Haskell Compilation System, version X.X.X
$
$ haskell-debug-adapter --version
VERSION: haskell-debug-adapter-0.0.XX.0
$

Cabal

Install ghci-dap, haskell-debug-adapter.

$ cabal update
$
$ cabal install ghci-dap haskell-debug-adapter
$
$ haskell-debug-adapter --version
VERSION: haskell-debug-adapter-0.0.XX.0
$

Run

1. Create a project

Stack project

$ mkdir project_stack
$ cd project_stack
$
$ stack new sample --bare
$ stack test
$

Cabal project

$ mkdir project_cabal
$ cd project_cabal
$
$ cabal init
$ cabal configure
$ cabal bulid
$

2. VSCode debug setting

3. Select a debug configuration

Stack project

Cabal project

4. Put a breakpoint

5. Start debugging

Configuration

see sample files.

.vscode/launch.json

NAME	REQUIRED OR OPTIONAL	DEFAULT SETTING	DESCRIPTION
startup	required	${workspaceRoot}/test/Spec.hs	debug startup file, will be loaded automatically.
startupFunc	optional	"" (empty string)	debug startup function, will be run instead of main function.
startupArgs	optional	"" (empty string)	arguments for startup function. set as string type.
stopOnEntry	required	false	stop or not after debugger launched.
mainArgs	optional	"" (empty string)	main arguments.
ghciPrompt	required	H>>=	ghci command prompt string.
ghciInitialPrompt	optional	"Prelude> "	initial pormpt of ghci. set it when using custom prompt. e.g. set in .ghci
ghciCmd	required	cabal repl -w ghci-dap --repl-no-load --builddir=${workspaceFolder/.vscode/dist-cabal-repl	launch ghci command.
ghciEnv	required	{}	Environment variables for ghci exectution.
logFile	required	${workspaceRoot}/.vscode/phoityne.log	internal log file.
logLevel	required	WARNING	internal log level.
forceInspect	required	false	Inspect scope variables force.