[Haskell-cafe] ANNOUNCE: Haskell XML Toolbox Version 9.0.0

Uwe Schmidt uwe at fh-wedel.de
Mon Oct 11 08:24:32 EDT 2010

Hello Henning,

> hxt-filter does not seem to be updated to hxt-9.0. How about providing
> hxt-filter with DEPRECATED pragmas for the functions that tell me how to
> rewrite functions from hxt-filter to arrows? Or is there another guide
> about how to move from hxt-filter to arrows?

Sorry, but there is no complete guide for rewriting filter code
into code working with arrows because of lack of time. Besides
developing and documenting hxt, there are a few other things,
that have to be done.

It's rather easy to convert to the arrow style.
All the functionality of hxt-filter is available in hxt.
Most of the names and operators remain as they are.

type XmlFilter = LA XmlTree XmlTree

That's the equivalent arrow type.
When evaluating a filter expression, use

runLA filter input

When switching to the arrow style, some of the operators
had to be renamed to the standard arrow operators,
e.g. (.>) to (>>>) and (+++) ==> (<+>)

For the monadic filters, mainly used for filters with IO
use the Type "IOSArrow XmlTree XmlTree" and
start a computation with runX, as described in the
examples of the wiki page about hxt:

Just compile your sources with these changes, and use
the Haskell compiler for finding ALL points, where you have
to modify or rename something.
If the code compiles, it will run.

Please trust in strong typing,


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