Haddock version during build

[Simon Peyton-Jones]

| -----Original Message-----
| From: David Waern
|
| How will upgrades of Haddock be handled?


| -----Original Message-----
| From: Manuel M T Chakravarty
| I agree with Ian.  Anything but bundling Haddock with GHC is going to
| lead to a big mess.  Here some reasons:
|
| * If you have multiple versions of GHC installed, you likely need
| multiple versions of Haddock.  Keeping those in sync separately is a
| pain.
|
| * Providing Haddock with a library path at install time is infeasible
| for Linux packages managers and similar.
|
| * Automatically searching for a matching GHC is fragile and OS
| dependent.  It also often won't work; eg, when building a binary-dist
| for a compiler that you haven't installed on your system - I do that
| very often.


To answer both (in my limited understanding).  The way Simon put it to me is: Haddock is like a GHC library.
  * We do indeed ship a lot of precompiled libraries with GHC
  * However, libraries can be upgraded without installing a fresh GHC
  * But, if you are using precompiled libraries, you must be very careful
        to install a new library with the correct GHC. If you have two
        installations of GHC, and you want to upgrade package P for both
        that's two separate operations.

So upgrading Haddock could be like upgrading a library.


I don't grok the details, but that seems like the right principle.

Simon