You must have missed the bit about "congenitally lazy" :-) Username requested ... cheers, Fraser. On Mon, Feb 16, 2009 at 8:10 PM, Lennart Augustsson wrote:

Put it on hackage!

...

Since I'm congenitally lazy, and writing a GUI by hand in the IO monad is ... not what I expect from a beautiful program, and because what I often need is a GUI that manipulates a state, and because I don't understand arrows, and having been intrigued by a recent cafe thread, I threw together a prototype GUI library with the following features:

- the GUI is defined on three levels: gadgets, widgets and styles - gadgets are functions on a state - widgets are data structures which define the layout - styles are ways to modify the appearance of widgets

The following quick example shows a text box and a button. Clicking on

...

button reverses the text in the text box.

...

module Main where

...

import Barrie

...

demoWidget :: Widget demoWidget = vbox [ui "demo entry" textBox, ui "demo command" (labelButton "click me")]

...

type DemoState = String

...

type DemoGadget = Gadget DemoState

...

demoGUI :: DemoGadget demoGUI = localG "demo gui" [editorG "demo entry" id const, commandG "demo command" reverse]

...

main = gtkMain demoGUI demoWidget "Hello, world"

Two gadgets are used:

editorG :: String -> (a -> b) -> (b -> a -> a) -> Gadget a commandG :: String -> (a -> a) -> Gadget a

The editor gadget can show a value from a state, and update a state with a value. The command gadget can transform a state to a new state. gtkMain connects the gadgets to a widget, which specifies layout using the vbox, attaching the editor gadget to a text box, and the command gadget to a button.

Well, that's all pretty trivial. The key thing for me was that I can easily slap a GUI onto the the front of a class of applications, which happen to be the sort of applications I've been writing lately. Also, arbitrary parts of the GUI can respond to things that happen miles away, without really having to worry about it too much. In barrie-0.1 and 0.2, which used stream-based approaches, the problem of getting state from one end of the application to the other was non-trivial.

I'll sketch another quick example:

...

data BridgeGame = ...

And a bunch of things you can do with the state:

...

makeBid :: Bid -> BridgeGame -> BridgeGame playCard :: Card -> BridgeGame -> BridgeGame

For bidding, each bid is represented by a gadget:

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bidG :: Bid -> Gadget BridgeGame bidG bid = enabled (bidOK bid) $ CommandG (show bid) (makeBid bid)

'enabled' switches the gadget on if its first argument returns true when applied to the current state. However, the decision about what to do with a disabled gadget is made by its corresponding widget.

We get one button for each bid:

...

biddingG :: Gadget BridgeGame biddingG = localG "bidding" (map bidG allBids)

And they can be displayed in any old order using a widget:

...

biddingW :: Widget biddingW = vbox (map suitBids [Club, Diamond, Heart, Spade] ++ [ntBids]) where suitBids suit = hbox $ map (bidButton . flip Bid suit) [1 .. 7] ntBids = hbox $ map (bidButton . NT) [1 .. 7] bidButton bid = ui (show bid) $ labelButton (show bid)

(You're right, double, redouble and pass are not represented. They make

2009/2/16 Fraser Wilson : the the

...

lines too long).

Screenshot here: http://thewhitelion.org/images/4D.png

I've just bid four diamonds, so everything lower than that is automatically disabled.

Currently, Barrie implements buttons, text boxes, labels, vertical/horizontal layout, single-column lists and drop lists. It current uses Gtk2hs for rendering, but it's GUI-agnostic (in fact, the first renderer was putStrLn/getLine).

You can have a look by using darcs: darcs get http://thewhitelion.org/darcs/barrie

Or get the tarball at http://thewhitelion.org/haskell/barrie-0.3.0-src.tar.gz

One note: this is not intended to be a theoretically sound approach, merely a way of getting something done quickly. I would expect it to be most useful in putting a GUI front-end onto an existing application, in particular, an application that is driven by user actions which update a state; e.g. a calculator, a bridge game, a 4th edition D&D character creator (but that leads to a critical mass of nerdiness, so it's off the table for now)

cheers, Fraser.

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Now that I re-read my email, it looks like I'm saying "Username requested" in the sense of "OK, Cafe people, treat this as a user name request and step to it." What I meant was that I have requested a username (via the email), and once I have an account I'll put it on hackage. Sorry for the confusion. Also, a patch that derives the Monoid instance for Style has been pushed. Let me explain why I love this mailing list. I hadn't really looked at Monoids, but then their utility fell out of the recent discussion about whether they should be called Monoids or ... whatever the other name was. And now I see them all over the place, and I'm a better person for it. Surely this is too much to be considered actual programming! cheers, Fraser. On Mon, Feb 16, 2009 at 10:40 PM, Duncan Coutts

wrote:

On Mon, 2009-02-16 at 20:30 +0100, Fraser Wilson wrote:

...

You must have missed the bit about "congenitally lazy" :-)

Username requested ...

See http://hackage.haskell.org/packages/accounts.html

All you need to do is email Ross and ask.

Duncan

-- http://thewhitelion.org/mysister

Hi Peter, Thanks! I haven't tried to compile with 0.10.0 but I can guess that the errors arise from the use of ListStore. I'm not sure what the best approach is here. Is 0.9.13 over now? If so, then I'll upgrade and fix it. For now it would certainly make sense to put the dependency into the cabal file, which I'm ashamed to say never occorred to me. cheers, Fraser On 17 feb 2009, at 00:29, Peter Verswyvelen wrote:

That's some great hacking you did :-)

What version of GTK2HS did you use? I get various compiler errors when using the latest GTK2HS 0.10.0.

Cheers, Peter

2009/2/16 Fraser Wilson Now that I re-read my email, it looks like I'm saying "Username requested" in the sense of "OK, Cafe people, treat this as a user name request and step to it." What I meant was that I have requested a username (via the email), and once I have an account I'll put it on hackage.

Sorry for the confusion.

Also, a patch that derives the Monoid instance for Style has been pushed. Let me explain why I love this mailing list. I hadn't really looked at Monoids, but then their utility fell out of the recent discussion about whether they should be called Monoids or ... whatever the other name was. And now I see them all over the place, and I'm a better person for it.

Surely this is too much to be considered actual programming!

cheers, Fraser.

On Mon, Feb 16, 2009 at 10:40 PM, Duncan Coutts

...

wrote: On Mon, 2009-02-16 at 20:30 +0100, Fraser Wilson wrote: You must have missed the bit about "congenitally lazy" :-)

Username requested ...

See http://hackage.haskell.org/packages/accounts.html

All you need to do is email Ross and ask.

Duncan

-- http://thewhitelion.org/mysister

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The current darcs version now mentions the 0.9.13 dependency. I don't see a nice way of supporting both 0.9.13 and 0.10.0, so I'll take the plunge and do a destructive upgrade. As you say, the new model/view is much nicer (and of course I shall be stealing liberally from it). cheers, Fraser. On Tue, Feb 17, 2009 at 11:16 AM, Peter Verswyvelen wrote:

Okay, you used 0.9.13, that explains the errors yes, the model/view thing is different in 0.10.0 (better IMHO) Yes it would be nice if it worked with GTK2HS 0.10.0, but it might be tricky to support both version, I don't know.

On Tue, Feb 17, 2009 at 12:51 AM, Fraser Wilson wrote:

...

Hi Peter,

Thanks!

I haven't tried to compile with 0.10.0 but I can guess that the errors arise from the use of ListStore. I'm not sure what the best approach is here. Is 0.9.13 over now? If so, then I'll upgrade and fix it.

For now it would certainly make sense to put the dependency into the cabal file, which I'm ashamed to say never occorred to me.

cheers, Fraser

On 17 feb 2009, at 00:29, Peter Verswyvelen wrote:

That's some great hacking you did :-)

What version of GTK2HS did you use? I get various compiler errors when using the latest GTK2HS 0.10.0.

Cheers, Peter

2009/2/16 Fraser Wilson < blancolioni@gmail.com>

...

Now that I re-read my email, it looks like I'm saying "Username requested" in the sense of "OK, Cafe people, treat this as a user name request and step to it." What I meant was that I have requested a username (via the email), and once I have an account I'll put it on hackage.

Sorry for the confusion.

Also, a patch that derives the Monoid instance for Style has been pushed. Let me explain why I love this mailing list. I hadn't really looked at Monoids, but then their utility fell out of the recent discussion about whether they should be called Monoids or ... whatever the other name was. And now I see them all over the place, and I'm a better person for it.

Surely this is too much to be considered actual programming!

cheers, Fraser.

On Mon, Feb 16, 2009 at 10:40 PM, Duncan Coutts < duncan.coutts@worc.ox.ac.uk> wrote:

...

On Mon, 2009-02-16 at 20:30 +0100, Fraser Wilson wrote:

...

You must have missed the bit about "congenitally lazy" :-)

Username requested ...

See http://hackage.haskell.org/packages/accounts.html http://hackage.haskell.org/packages/accounts.html

All you need to do is email Ross and ask.

Duncan

-- http://thewhitelion.org/mysisterhttp://thewhitelion.org/mysister

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