[Haskell] ANN: Barrie 0.3.1

Fraser Wilson blancolioni at gmail.com
Tue Feb 17 17:05:50 EST 2009


This is the hackaged version of an earlier release of Barrie.  This release
is not backward compatible (but it took me about five minutes to update
everything).

>From the package description:

    Implementation of an idea for supporting certain kinds of GUI:
    that is state based, user-driven ones.  The GUI is intended to
    manipulate a state, and it is responsive rather than active.
    Configuration is an example.

The idea is that you already have a state-manipulation bit of code lying
around, and you want to slap a GUI on the front.  Barrie does not help you
write beautiful code, but it sure puts something functional on the screen
quickly.  It's currently being used for an interface to a Bridge
application, and for something else which is too nerdy to describe here, but
which follows the general pattern of the intended purpose.

To install:
$ cabal update
$ cabal install barrie

Barrie now requires gtk2hs 0.10.0.

<http://hackage.haskell.org/cgi-bin/hackage-scripts/package/barrie>Changes:

- Dropped the generic value type.

It was
      1. not type safe
      2. not interesting
      3. not exactly everything I ever wanted from a type-agnostic storage
mechanism.

Instead, Barrie operates internally with Strings.  This should be type safe
because of the way they are wrapped, and it seems like a good place to park
the problem until I work out what I really want.

- Gadget constructors are now much more regular.  For example, to create a
gadget that displays things, you have a choice of displayG, which displays
any instance of show, displayG', which lets you provide your own conversions
to and from String, and textDisplayG, which displays plain old Strings.
Similarly, the chooserG gadget is created by chooserG, chooserG' and
textChooserG, but there's also enumChooserG, which automatically creates a
chooser for the elements of any Enum that is an instance of Show.  Choosers
can currently be rendered by a list or a combo box.

- Quite a bit of documentation, which, because of the regularity imposed by
Haddock, is making me question the decision to use Literate Haskell.  Hey
ho, live and learn.

- Text boxes now apply their changes after they lose focus.

The darcs repository with demos can still be found at
http://thewhitelion.org/darcs/barrie, and I think I've sorted out the recent
problems there.

cheers,
Fraser.

-- 
http://thewhitelion.org/mysister
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