List of GHC extensions

Question

I wanted to use {-# LANGUAGE OverloadedStrings #-} but I forgot how it's called. This kind of thing isn't hoogle-able, and also it takes some time finding using google*.

Is there somewhere a list of GHC extensions named as they are in the LANGUAGE pragma?

* My googling search journey:

• Google
• Haskell at wikipedia
• GHC at wikipedia
• GHC language features
• Overload string literals
• OverloadedStrings

Answer 1

The "Language options" section of the flag reference page has a list that's much more easily browseable than the language features page.

Once you're there a Ctrl-F search for "overloaded" takes you right to what you want.

Answer 2

ghci's tab-completion knows. Type :set -X at a ghci prompt, then hit Tab, and you'll get a full list. Or :set -XFoo then Tab will get you a list of all extensions beginning with Foo.

Answer 3

ghc-mod for Emacs found here: http://hackage.haskell.org/package/ghc-mod-0.4.1, includes completion for language extensions. If you are an Emacs user, I suggest you to try it.

Answer 4

$ ghc --supported-languages

(from GHC docs)

Answer 5

When using Leksah IDE, selecting Package menu, then Edit Package menu item, then Extension tab also gives you a checkable list.