gedit: Single line text edit constructor
In jverzani/gWidgets2: Rewrite of gWidgets API for Simplified GUI Construction

The default change handler is called when the return key is pressed. It can be useful to also call a handler when the widget loses focus. For that, the addHandlerBlur method is of use. (This was the default, but is now not, as it was hard to decouple the two when that was desirable.)

generic for toolkit dispatch

The default change handler call is when the user activates the entry by pressing the enter key. Other possible events to consider are covered by: addhandlerBlur (when the widget loses focuses) and addHandlerKeystroke (called after each keystroke). For the latter, if the toolkit supports it, the handler's first argument has a component key passing back the keystroke information.

The svalue method for a edit object refers to its main property, the text in the box.

gedit(text = "", width = 25, coerce.with = NULL, initial.msg = "",
  handler = NULL, action = NULL, container = NULL, ...,
  toolkit = guiToolkit())

.gedit(toolkit, text = "", width = 25, coerce.with = NULL,
  initial.msg = "", handler = NULL, action = NULL, container = NULL,
  ...)

## S3 method for class 'GEdit'
addHandlerChanged(obj, handler, action = NULL, ...)

## S3 method for class 'GEdit'
svalue(obj, index = NULL, drop = NULL, ...)

`text`	initial text
`width`	number of characters
`coerce.with`	A function or name of function to coerce value with before returning by `svalue`
`initial.msg`	If no initial text is given but an initial message is, then this message is displayed until the widget receives the focus
`handler`	Change handler. Called when return key is hit. Use `addHandleBlur` to add a handler when the widget loses focus, such as through tab-key navigation.
`action`	passed to handler
`container`	parent container
`...`	passed to `add` method of parent
`toolkit`	toolkit
`obj`	object receiving event and emitting a signal to the handler
`index`	NULL or logical. If `TRUE` and widget supports it an index, instead of a value will be returned.
`drop`	NULL or logical. If widget supports it, drop will work as it does in a data frame or perhaps someother means.