This closes issue #38 by adding a missing field to get and extract.
Previously the default behavior for missing values was to return an NA, this PR changes the default behavior to returning a NULL. NULL is more in line with R convention for extracting a missing value (like a nonexistent entry in a list, for instance). So this does break existing behavior, but since the missing field exists if people want the NA they can easily set it back.
This closes issue #38 by adding a
missing
field to get and extract.Previously the default behavior for missing values was to return an NA, this PR changes the default behavior to returning a NULL. NULL is more in line with R convention for extracting a missing value (like a nonexistent entry in a list, for instance). So this does break existing behavior, but since the missing field exists if people want the NA they can easily set it back.