I'm trying to make a text control that allows only letters and spaces, and
changes letters to underscores* as you type*. So if you typed "abc123 def",
you would see "___ ___" appearing.
I thought the solution would be
controlOnText<http://hackage.haskell.org/packages/archive/wxcore/0.10.1/doc/html/Graphics-UI-WXCore-Events.html#v%3AcontrolOnText>,
which is nice because it works with both keyboard input and pasting. The
problem is it also gets called when I change the text using set. For example
here's a simple program that just reads the text and sets it again:
module Main where
import Graphics.UI.WX
import Graphics.UI.WXCore
main = start $
do f <- frame []
input <- textEntry f []
controlOnText input $ update input
where
update input =
do txt <- get input text
set input [text := txt]
This doesn't work because it results in an infinite loop. In wxPython I can
use ChangeValue instead of SetValue to change the text without creating an
event, but I can't find anything like that in wxHaskell. Is there another
way to do this?
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