nil?
nil?
The pseudo-method nil?
determines whether an expression's runtime is Nil
. For example:
a = 1 a.nil? # => false b = nil b.nil? # => true
It is a pseudo-method because the compiler knows about it and it can affect type information, as explained in if var-nil?(---)-
It has the same effect as writing is_a?(Nil)
but it's shorter and easier to read and write-
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https://crystal-lang.org/docs/syntax_and_semantics/nil_question.html