unloadable

Mark the given constant as unloadable. Unloadable constants are removed each time dependencies are cleared.

Note that marking a constant for unloading need only be done once. Setup or init scripts may list each unloadable constant that may need unloading; each constant will be removed for every subsequent clear, as opposed to for the first clear.

The provided constant descriptor may be a (non-anonymous) module or class, or a qualified constant name as a string or symbol.

Returns true if the constant was not previously marked for unloading, false otherwise.