+/* Returns TRUE if all of the variable(s) represented by the rows
+ currently selected by SOURCE widget, are numeric. DEST is ignored.
+
+ In other words, this function when passed as the argument to
+ psppire_selector_set_allow, ensures that the selector selects only
+ numeric variables.
+*/
+gboolean numeric_only (GtkWidget *source, GtkWidget *dest);
+
+/*
+ A pair of functions intended to be used as callbacks for the "toggled" signal
+ of a GtkToggleButton widget. They make the sensitivity of W follow the status
+ of the togglebutton.
+*/
+void set_sensitivity_from_toggle (GtkToggleButton *togglebutton, GtkWidget *w);
+void set_sensitivity_from_toggle_invert (GtkToggleButton *togglebutton, GtkWidget *w);
+