NAME 
src/pmc/undef.pmc - Generic undefined value
DESCRIPTION
This is Parrot's generic undef type. This PMC has no defined value. It returns a numeric value of 0, a boolean of false, and an empty string. When assigned a number, integer, or string it morphs to a Number, Integer, or String PMC respectively, and when assigned a generic PMC it morphs into a PMC of the passed-in type and does a same-type assignment from there.
