[Haskell-cafe] A cabal odyssey

[Duncan Coutts]

On 19 August 2010 21:15, Andrew Coppin <andrewcoppin at btinternet.com> wrote:
> Daniel Fischer wrote:

>> Yes, when cabal runs haddock on a package, it generates a comprehensive
>> index if none is present or expands it with the new docs.
>> Quite cool that :)
>>
>
> It's something I've always _wanted_ Cabal to do, but this is the first time
> I've ever seen it happen. I don't know what particularly I did to make this
> happen, and now it seems to be gone, so...

If you have documentation enabled then it is recreated every time you
install a package.

(Though only for user packages, since we have not yet worked out
somewhere sensible we can stick a global index).

> I gathered. Apparently there's no "cabal uninstall" or even merely a "cabal
> unregister" yet... (There must surely be a ticket for that already?)

Yup, there's a ticket for it.

> Well, the worst thing that can happen is I get no documentation, which isn't
> exactly a disaster. I'm just wondering how these files got created to start
> with; adding more packages doesn't appear to recreate it. I suppose I could
> try reinstalling all of them...

If you have documentation enabled (ie use --enable-documentation on
the command line, or have "documentation: True" in the ~/.cabal/config
file) then docs get created for each package you install, and the
haddock index/contents of all installed docs gets updated.

>>> Then again, all the links were broken anyway. They all had paths like
>>> "C:\Program Files\Haskell\...whatever", and Mozilla apparently expects
>>> them to say "file://C:/Program Files/Haskell/...whatever". It kept
>>> whining that "the C:\ protocol is not registered"
>>
>> Apparently, haddock links to absolute paths. That's of course not the
>> right thing to do if the path begins with an invalid protocol specifier
>> ("C:"). And it's annoying if you want to move the docs.
>>
>
> I imagine it's so that each package can be placed in a completely arbitrary
> place in the filesystem, and the links still work. I'd actually be surprised
> if these URLs work on Linux either; they don't appear to follow the requisit
> web standards.

You may be right, or perhaps URL syntax is just liberal enough to let
unix style paths work. It's still a bug of course that we're not using
the file:// protocol which makes it not work on windows. I filed it
here:
http://hackage.haskell.org/trac/hackage/ticket/516#comment:6

Duncan