This function causes the pattern search to be performed against an object's values instead of its names
pattern for which to match against an objects values
In order to perform a reverse lookup, values must be converted to character names.
a string object with the
reversse.lookup attribute set.
When performing a reverse lookup, values (not names) are searched. The corresponding names are returned. NOTE: this is highly experimental and only works for atomic vectors. It is uncertain how this might be applied to recursive structures like lists.
What happens if there are two reverse.lookups
invert function in the