public void execute(jetbrains.mps.openapi.editor.EditorContext context) {
SelectionManager selectionManager =
((EditorComponent) context.getEditorComponent()).getSelectionManager();
SingularSelection selection = (SingularSelection) selectionManager.getSelection();
if (!expandSelection(selection) && selectionManager.getSelectionStackSize() > 1) {
selectionManager.popSelection();
return;
}
EditorCell selected = selection.getEditorCell();
EditorCell nextLeaf = getNextLeaf(selected);
EditorCell cellToSelect = getCommonSelectableAncestor(selected, nextLeaf);
Selection newSelection = selectionManager.createSelection(cellToSelect);
if (newSelection instanceof SingularSelection) {
((SingularSelection) newSelection)
.setSideSelectDirection(
mySide == CellSide.LEFT ? SideSelectDirection.LEFT : SideSelectDirection.RIGHT);
}
selectionManager.pushSelection(newSelection);
}