gvarbrowser: Constructor for workspace variable browser

In gWidgets2: Rewrite of gWidgets API for Simplified GUI Construction

Description

A workspace browser widget. The workspace browser displays values in the global environment. Displayed objects are shown in categories.

Return selected objects a string (when drop=TRUE) with recursive values separated by $, or the objects themselves (when drop=FALSE).

Usage

gvarbrowser(
  handler = NULL,
  action = "summary",
  container = NULL,
  ...,
  toolkit = guiToolkit()
)

.gvarbrowser(
  toolkit,
  handler = NULL,
  action = "summary",
  container = NULL,
  ...
)

## S3 method for class 'GVarBrowser'
svalue(obj, index = FALSE, drop = TRUE, ...)

Arguments

handler	A handler assigned to the default change signal. Handlers are called when some event triggers a widget to emit a signal. For each widget some default signal is assumed, and handlers may be assigned to that through addHandlerChanged or at construction time. Handlers are functions whose first argument, h in the documentation, is a list with atleast two components obj, referring to the object emitting the signal and action, which passes in user-specified data to parameterize the function call. Handlers may also be added via addHandlerXXX methods for the widgets, where XXX indicates the signal, with a default signal mapped to addHandlerChanged (cf. addHandler for a listing). These methods pass back a handler ID that can be used with blockHandler and unblockHandler to suppress temporarily the calling of the handler.
action	User supplied data passed to the handler when it is called
container	A parent container. When a widget is created it can be incorporated into the widget heirarchy by passing in a parent container at construction time. (For some toolkits this is not optional, e.g. gWidgets2tcltk or gWidgets2WWW2.)
...	These values are passed to the add method of the parent container. Examples of values are expand, fill, and anchor, although they're not always supported by a given widget. For more details see add. Occasionally the variable arguments feature has been used to sneak in hidden arguments to toolkit implementations. For example, when using a widget as a menubar object one can specify a parent argument to pass in parent information, similar to how the argument is used with gaction and the dialogs.
toolkit	Each widget constructor is passed in the toolkit it will use. This is typically done using the default, which will lookup the toolkit through guiToolkit.
obj	object of method call
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.

Details

For defining the categories, the reference method set_filter_classes takes a named list, the names defining the categories, the values being the classes belonging to that category. Non categorized values appear separately. The default is defined in gWidgets2:::gvarbrowser_default_classes.

The variable browser uses an instance of WSWatcherModel to monitor the global workspace. This instance may be useful for other purposes. (For example, one may add an observer that is called to listen for changes to the set of available data frames.). The instance is available through the ws_model property.

The svalue method returns the selected variable names. If drop=FALSE is given, the objects are returned.

The widget should support dragging from without needing to specify a drag_source, though this may be overridden.

Use addHandlerChanged to listen to activation of a variable (double clicking). Use addHandlerSelectionChanged to monitor change of selection.

gWidgets2 documentation built on Jan. 11, 2022, 1:07 a.m.