I am working through some Clojure tutorials and one of the problems is: Implement (boolean x), which works like the built-in boolean function: for nil and false, it returns false, and for all other values it returns true. You can use if in its implementation, but not the build-in boolean.
I cannot figure out how to do this with just the if statement. This works, but is there a better way?
_Module答案 0 :(得分：4)
gradlew assembleProdStaging
gradlew crashlyticsUploadDistributionProdStaging
and nil are both 'falsey' (i.e. are equivalent to false in a boolean context) so you can do:
false(defn boolean [x]
(if x true false))
expressions are of the form if so if (if condition true-expr false-expr) evaluates to condition the entire expression evaluates to true otherwise true-expr. So if false-expr is x (i.e. not truthy or nil) the expression will evaluate to false. If true is x (falsey and nil are the only falsey values in clojure) then false is returned.
答案 1 :(得分：1)
maybe like this?
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