Fedora 13 Update: ghc-neither-0.1.0-1.fc13

updates at fedoraproject.org updates at fedoraproject.org
Mon Jan 3 20:02:15 UTC 2011


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Fedora Update Notification
FEDORA-2010-18820
2010-12-11 23:34:05
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Name        : ghc-neither
Product     : Fedora 13
Version     : 0.1.0
Release     : 1.fc13
URL         : http://hackage.haskell.org/package/neither
Summary     : Either with monad and applicative instances
Description :
The standard Either datatype suffers from a lack of monad and
applicative instances. To make matters worse, the mtl and
transformers packages provide orphan instances which conflict
with each other, as well as defining a transformer version
which has an usually unnecessary superclass constraint.

Besides these annoyances, there is another issue: there exist
two reasonable definitions of the Applicative instance for
Either: one the holds onto only the first Left value, or one
that appends all Left values together via a Monoid instance.
The former is compatible with the monad instance, while the
latter is not.

This package defines three datatypes, some helpers functions
and instances. The data types are AEither, MEither and
MEitherT. AEither provides an Applicative instance which
appends Left values, MEither provides the monadic definition,
and MEitherT is a monad transformer.

This package provides the shared library.

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Update Information:

A simple type class for success/failure computations.

===============

The standard Either datatype suffers from a lack of monad and
applicative instances. To make matters worse, the mtl and
transformers packages provide orphan instances which conflict
with each other, as well as defining a transformer version
which has an usually unnecessary superclass constraint.

Besides these annoyances, there is another issue: there exist
two reasonable definitions of the Applicative instance for
Either: one the holds onto only the first Left value, or one
that appends all Left values together via a Monoid instance.
The former is compatible with the monad instance, while the
latter is not.

This package defines three datatypes, some helpers functions
and instances. The data types are AEither, MEither and
MEitherT. AEither provides an Applicative instance which
appends Left values, MEither provides the monadic definition,
and MEitherT is a monad transformer.
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References:

  [ 1 ] Bug #630283 - Review Request: ghc-neither - Either with monad and applicative instances
        https://bugzilla.redhat.com/show_bug.cgi?id=630283
  [ 2 ] Bug #630223 - Review Request: ghc-failure - A simple type class for success/failure computations
        https://bugzilla.redhat.com/show_bug.cgi?id=630223
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This update can be installed with the "yum" update program.  Use 
su -c 'yum update ghc-neither' at the command line.
For more information, refer to "Managing Software with yum",
available at http://docs.fedoraproject.org/yum/.

All packages are signed with the Fedora Project GPG key.  More details on the
GPG keys used by the Fedora Project can be found at
https://fedoraproject.org/keys
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