Feature #17773

Updated by sawa (Tsuyoshi Sawada) about 1 year ago

When dealing with user input fields as in web applications, there are typical values that we want to consider as the default and/or absence of user input. For string/text inputs, list items, and attributes, we have `String#empty?`, `Array#empty?`, and `Hash#empty?` respectively, which seem to correspond to those cases. As for numerics, there are `Numeric#zero?` and `Float#zero?`. 

 However, there is no single term that covers all these cases. In a routine to check through the fields whether there is user input, we have to selectively use `empty?` or `zero?` depending on the type of the input field. 

 Many programming languages other than Ruby typically consider these values as falsy with respect to logical calculation. Ruby handles only `nil` and `false` as falsy, and that has clear advantages in many aspects, but with the cost of losing a simple way to handle these default values. 

 I propose to alias `Numeric#zero?` as `Numeric#empty?` and `Float#zero?` as `Float#empty?` so that we can simply use `empty?`. At first, calling zero as empty might sound strange, but at least for non-negative integers, set theoretic definitions usually define zero as the empty set, so it is not that strange after all. 

 Ruby on Rails' `blank?` is conceptually similar to this, but `0.blank?` returns `false`, so it is a different concept.