libmoosex-setonce-perl - 0.200002-2 main

MooseX::SetOnce provides the SetOnce attribute which lets your class have
attributes that are not lazy and not set, but that cannot be altered once
set.
.
The logic is very simple: if you try to alter the value of an attribute with
the SetOnce trait, either by accessor or writer, and the attribute has a
value, it will throw an exception.
.
If the attribute has a clearer, you may clear the attribute and set it again.