13 lines
535 B
Clojure
13 lines
535 B
Clojure
(defn bind [val f]
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(if-let [v (:value val)] (f v) val))
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(defn unit [val] {:value val})
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(defn opt_add_3 [n] (unit (+ 3 n))) ; takes a number and returns a Maybe number
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(defn opt_str [n] (unit (str n))) ; takes a number and returns a Maybe string
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(bind (unit 4) opt_add_3) ; evaluates to {:value 7}
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(bind (unit nil) opt_add_3) ; evaluates to {:value nil}
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(bind (bind (unit 8) opt_add_3) opt_str) ; evaluates to {:value "11"}
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(bind (bind (unit nil) opt_add_3) opt_str) ; evaluates to {:value nil}
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