check if given attribute exists

Parameters

attr? name :string :literal

Returns

Examples

copy
greet: function [x][
    switch attr? 'later
      -> ~"|x| I'm afraid, I'll greet you later"
      -> ~"Hello, |x|!"
]

greet "John"
; => Hello, John!

greet.later "John"
; => John I'm afraid, I'll greet you later!

; Have in mind that `attr?` won't pop your attribute's stack

greet "Joe"
; => Joe I'm afraid, I'll greet you later!

Related