[arch-haskell] [jgm@berkeley.edu: Re: Pandoc restriction for Parsec <3]

Don Stewart dons at galois.com
Mon Feb 15 20:09:59 EST 2010

The main user of parsec -- pandoc -- is *not* going to move to parsec 3,
since it is twice as slow.

That means that neither is the Haskell Platform

That means that we should downgrade to parsec 2 on arch and *not move to
parsec 3 for the foreseeable future*.

-- Don

----- Forwarded message from John MacFarlane <jgm at berkeley.edu> -----

Date: Mon, 15 Feb 2010 16:59:32 -0800
From: John MacFarlane <jgm at berkeley.edu>
To: Don Stewart <dons at galois.com>
Cc: Peter Simons <simons at cryp.to>
Subject: Re: Pandoc restriction for Parsec <3


Peter Simons says that pandoc won't build on arch because parsec 2 is
not available there, and pandoc depends on parsec < 3. I don't want to
change that dependency, because when compiled against the current parsec
3, pandoc is about twice as slow as when compiled against parsec 2.

Peter proposes uploading a new 'open-pandoc' package with the parsec
restriction removed. I think that will just confuse users who want to
install pandoc; a better solution, obviously, would be for parsec 2 to
be made available on Arch. I don't know why it wouldn't be; after all,
parsec 2 is (last I checked) still the version in the Haskell platform,
and the default for cabal-install; and many Hackage packages besides
pandoc depend on parsec < 3.

So I thought I'd ping you to see what the story is; please cc
Peter in your reply...


+++ Peter Simons [Feb 16 10 01:47 ]:
> Hi John,
>  > Suppose you're using pandoc in a web app that delivers up hundreds of
>  > pages, some quite long.
> if you do that, Pandoc is a mission-critical component in your setup and
> it's fine to dedicate extra effort to, say, building it with Parsec 2.
> For occasional users like me, however, the difference in performance is
> hardly measurable.
>  >> Well, if you don't want your software to work on ArchLinux, then this is
>  >> the way to go. It's your choice.
>  >
>  > It's not my fault that it doesn't work on Arch.
> Of course it is. You deliver a cabal file that refuses to build Pandoc
> with Parsec 3, even though it would build just fine! Who else do you
> think should be responsible for that?
> Anyway, I have found a solution that should work. I'll fix Pandoc's
> Cabal file and upload that version to Hackage calling it, say
> open-pandoc. The automatic cabal2arch converter will make that package
> available in ArchLinux within a couple of days, and then everything will
> be fine.
> Take care,
> Peter

----- End forwarded message -----

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