StateT和WX gui共存
通常的wxHaskell程序看起来像
main = do
run gui
gui = do
....
....
gui必须有类型IO a，运行有类型IO a -> IO()，在run中还有一些初始化例程。
我尝试执行以下操作：
data AppGlobals = AG { ... some data ... }
type MApp a = StateT AppGlobals IO a
但在这种情况下，gui 必须具有类型 gui :: MApp AppGlobals。由于它的类型，不可能使用通常的 IO monad 语法，我的意思是每次执行 IO 操作时我都必须使用 liftIO 。
在 wxHaskell 中是否有方便使用 State monad 的可能性？手动将状态传递给每个事件处理程序不太方便。
usual wxHaskell program looks like
main = do
run gui
gui = do
....
....
gui must have type IO a, run has type IO a -> IO (), also there is some initialization routines in run.
I'm tring to do following:
data AppGlobals = AG { ... some data ... }
type MApp a = StateT AppGlobals IO a
But in this case gui must have type gui :: MApp AppGlobals. Due to it's type it becomes impossible to use usual IO monad syntax, I mean Ihave to use liftIO every time I performing IO action.
Is there Any convinient possibility to use State monad in wxHaskell? It's not very convinient to pass state to each event handler manually.
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我读过和写过的 wxHaskell 程序只是将状态推入变量中。
http://wxhaskell.sourceforge.net/doc/Graphics-UI- WX-变量.html
这是一个很好的概述：
http://legacy.cs.uu.nl/daan/download/ paper/wxhaskell.pdf
他们使用启动而不是运行。
The wxHaskell programs I've read and written just shove the state into variables.
http://wxhaskell.sourceforge.net/doc/Graphics-UI-WX-Variable.html
Here's a good overview:
http://legacy.cs.uu.nl/daan/download/papers/wxhaskell.pdf
And they use start rather than run.
理论上是可行的，但我发现它在实践中很麻烦，就像你一样。我自己的 wxHaskell 代码通常看起来像我在引用的博客文章中描述的那样：
http://wewantarock.wordpress.com/2010/01/11/custom-controls-in-wxhaskell-part-3/
您可以按照 ja 的建议使用 wxHaskell 变量同样的目的，尽管我更喜欢在博客中使用的更明确的风格。
It's possible in theory, but I've found it to be cumbersome in practice, as you did. My own wxHaskell code usually looks something like I described in the referenced blog article:
http://wewantarock.wordpress.com/2010/01/11/custom-controls-in-wxhaskell-part-3/
You can use wxHaskell variables, as ja suggested, for the same purpose, although I prefer the more explicit style I used in the blog.