Haskell offline documentation?
What are the possibilities, if any, for getting offline docs for Haskell core libraries (and maybe more)?
Sometimes I take my laptop to the coffee-shop where there is no wifi, and it would be nice having something like Hoogle but for offline use.
Answer
Hoogle is available offline, installable from Cabal: http://hackage.haskell.org/package/hoogle
Usage instructions are at http://www.haskell.org/haskellwiki/Hoogle#Command_Line_Search_Flags.
Usage:
$ hoogle --help
Hoogle v4.2.8, (C) Neil Mitchell 2004-2011
http://haskell.org/hoogle
hoogle [COMMAND] ... [OPTIONS]
Commands:
[search] Perform a search
data Generate Hoogle databases
server Start a Hoogle server
combine Combine multiple databases into one
convert Convert an input file to a database
test Run tests
dump Dump sections of a database to stdout
rank Generate ranking information
log Analyse log files
Common flags:
-? --help Display help message
-V --version Print version information
-v --verbose Loud verbosity
-q --quiet Quiet verbosity
Create a default database with hoogle data (more info at http://neilmitchell.blogspot.com/2008/08/hoogle-database-generation.html).
EDIT: A session of usage after installing Hoogle locally:
$ hoogle
No query entered
Try --help for command line options
$ hoogle data
(downloads databases...takes a few minutes)
I ran into an error here...apparently it is related to the version of Cabal, so I updated that (http://hackage.haskell.org/trac/hackage/ticket/811). That didn't help, so I ran hoogle data all, which I canceled since it was taking so long (it seems to go through every package on Hackage). It still wouldn't allow a query like hoogle map but did allow hoogle map +base (i.e. restrict the search to the base package) Hopefully it works for you!
EDIT2: This seems to fix the problem (for me):
$cd .cabal/share/hoogle-4.2.8/databases
$hoogle combine base.hoo
$hoogle foldl\'
Data.List foldl' :: (a -> b -> a) -> a -> [b] -> a
Data.Foldable foldl' :: Foldable t => (a -> b -> a) -> a -> t b -> a