3 Examples top

• link | changes

  ;; Here are the definitions.
  (defn mymax [x y]
    (min x y))
  
  (defn find-max [x y]
    (max x y))
  
  user=> (let [max mymax]
           (find-max 10 20))
  
  20 ;let is ineffective outside current lexical scope
  
  
  user=> (binding [max mymax]
           (find-max 10 20))
  
  10 ;because max is now acting as min

  ;; Here are the definitions. (defn mymax [x y] (min x y)) (defn find-max [x y] (max x y)) user=> (let [max mymax] (find-max 10 20)) 20 ;let is ineffective outside current lexical scope user=> (binding [max mymax] (find-max 10 20)) 10 ;because max is now acting as min
• link | changes

  ;; As of Clojure 1.3, vars need to be explicitly marked as ^:dynamic in order for
  ;; them to be dynamically rebindable:
  
  user=> (def ^:dynamic x 1)
  user=> (def ^:dynamic y 1)
  user=> (+ x y)
  2
  
  ;; Within the scope of the binding, x = 2 and y = 3
  
  user=> (binding [x 2 y 3]
           (+ x y))
  5
  
  ;; But once you leave the binding's scope, x and y maintain their original
  ;; bindings:
  
  user=> (+ x y)
  2

  ;; As of Clojure 1.3, vars need to be explicitly marked as ^:dynamic in order for ;; them to be dynamically rebindable: user=> (def ^:dynamic x 1) user=> (def ^:dynamic y 1) user=> (+ x y) 2 ;; Within the scope of the binding, x = 2 and y = 3 user=> (binding [x 2 y 3] (+ x y)) 5 ;; But once you leave the binding's scope, x and y maintain their original ;; bindings: user=> (+ x y) 2
• link | changes

  ;;Use t like a "template"
  
  (declare ^:dynamic t)
  
  (defn addt [] 
    (+ t 10))
  
  (binding [t 1]
    (addt))
  => 11

  ;;Use t like a "template" (declare ^:dynamic t) (defn addt [] (+ t 10)) (binding [t 1] (addt)) => 11