ghciwatch

Ghciwatch loads a GHCi session for a Haskell project and reloads it when source files change.

Features

• GHCi output is displayed to the user as soon as it’s printed.
• Ghciwatch can handle new modules, removed modules, or moved modules without a hitch
• A variety of lifecycle hooks let you run Haskell code or shell commands on a variety of events.
  • Run a test suite with --test-ghci TestMain.testMain.
  • Refresh your .cabal files with hpack before GHCi starts using --before-startup-shell hpack.
  • Format your code asynchronously using --before-reload-shell async:fourmolu.
• Custom globs can be supplied to reload or restart the GHCi session when non-Haskell files (like templates or database schema definitions) change.
• Ghciwatch can clear the screen between reloads.
• Compilation errors can be written to a file with --error-file, for compatibility with ghcid’s --outputfile option.
• Comments starting with -- $> can be evaluated in GHCi.
  • Eval comments have access to the top-level bindings of the module they’re defined in, including unexported bindings.
  • Multi-line eval comments are supported with {- $> ... <$ -}.

Demo

Check out an asciinema demo to see how ghciwatch feels in practice: