My current favorite is in ruby with the unless keyword:
tax = 0.00
unless not_taxed(billing)
tax = billing.zipcode.blank? ? estimated_tax_from_ip(account) : billing.tax
tax = (tax.nil? ? 0.00 : tax)
end
To me, anything payments related you want to be really super clear as to what you're doing because the consequences of getting it wrong are your income. Instead we have this abomination of a double negative, several turnaries, and no comments.
Correct, and since there are multiple instances I'm using a plural form, and fighting autocorrect at the same time.