bipiped_value_to_vector: Convert a "bipiped" value (or vector of values) to a vector
Description
"Bipiped" means that different values are separated by a pair of
pipes (||), like the logical OR operator in R. Use
bipiped_value_to_vector() for single values, and
bipiped_values_to_vector() for a vector of values, in which case a list
is returned.