2 Examples top

• link | changes

  ;; Checking numbers
  user=> (type 10)
  java.lang.Integer
  
  user=> (type 10.0)
  java.lang.Double
  
  
  ;; Checking collections
  user=> (type [10 20])
  clojure.lang.PersistentVector
  
  user=> (type '(10 20))
  clojure.lang.PersistentList
  
  
  ;; Checking other, but somewhat intuitive, forms
  user=> (type :a)
  clojure.lang.Keyword
  
  user=> (type Thread)
  java.lang.Class
  
  
  ;; Checking a symbol
  user=> (type 'whatever)
  clojure.lang.Symbol
  
  ;; A surprise attack yields
  user=> (type clojure.lang.Symbol)
  ;; not such a surprising response
  java.lang.Class
  
  
  ;; Checking a function
  user=> (defn foo [] ("any string"))
  #'user/foo
  user=> (type foo)
  user$foo
  
  
  ;; Checking a macro
  user=> (type fn)
  user$fn
  
  user=> (type clojure.core/fn)
  java.lang.Exception: Can't take value of a macro: #'clojure.core/fn (NO_SOURCE_FILE:94)
  
  

  ;; Checking numbers user=> (type 10) java.lang.Integer user=> (type 10.0) java.lang.Double ;; Checking collections user=> (type [10 20]) clojure.lang.PersistentVector user=> (type '(10 20)) clojure.lang.PersistentList ;; Checking other, but somewhat intuitive, forms user=> (type :a) clojure.lang.Keyword user=> (type Thread) java.lang.Class ;; Checking a symbol user=> (type 'whatever) clojure.lang.Symbol ;; A surprise attack yields user=> (type clojure.lang.Symbol) ;; not such a surprising response java.lang.Class ;; Checking a function user=> (defn foo [] ("any string")) #'user/foo user=> (type foo) user$foo ;; Checking a macro user=> (type fn) user$fn user=> (type clojure.core/fn) java.lang.Exception: Can't take value of a macro: #'clojure.core/fn (NO_SOURCE_FILE:94)
• link | changes

  ;This example demonstrates how to add type information to regular clojure maps
  (defn purchase-order [id date amount]
    ^{:type ::PurchaseOrder} ;metadata
     {:id id :date date :amount amount})
  
  (def my-order (purchase-order 10 (java.util.Date.) 100.0))
  
  (my-order)
  => {:id 10, :date #<Date Sun May 15 14:29:19 EDT 2011>, :amount 100.0}
  
  (type my-order)
  => PurchaseOrder

  ;This example demonstrates how to add type information to regular clojure maps (defn purchase-order [id date amount] ^{:type ::PurchaseOrder} ;metadata {:id id :date date :amount amount}) (def my-order (purchase-order 10 (java.util.Date.) 100.0)) (my-order) => {:id 10, :date #<Date Sun May 15 14:29:19 EDT 2011>, :amount 100.0} (type my-order) => PurchaseOrder