CODEWITHSUNDEEP
haskellhelper
user10756
user10756

Reputation: 649

Haskell command line help from ghci

Does ghci have built-in help? Put differently, is it possible to get help from within ghci?

For example, I want to now all functions that can be applied to a list.

There is a useful command :info, which outputs some help, however it is a bit cumbersome.

Upvotes: 3

Views: 817

Answers (2)

chris
chris

Reputation: 5038

Since hoogle was already mentioned. You can easily integrate it into ghci by first installing the corresponding hackage package using cabal

cabal install hoogle

and then modifying your ~/.ghci as follows

echo >> ~/.ghci ':def hoogle \x -> return $ ":!hoogle \"" ++ x ++ "\""'

After that you can use :hoogle from within ghci.

Note: It might be necessary to do

hoogle data

on the command line, before the :hoogle command in ghci works.

Upvotes: 3

Aegis
Aegis

Reputation: 1789

You can type :? to get a list of all ghci commands. A very useful tool is hoogle which is a seearch engine for the Haskell API. You can search functions by their names or by their types, i.e:

(a -> b) -> [a] -> [b]
foldl
...

It provides a short description of the function and a link to its documentation. Hope it helped!

http://www.haskell.org/hoogle

Upvotes: 6

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