constructor - 使用 defrecord 构造函数调用 apply？

Question

core=> (defrecord Puffball [id name])
core.Puffball
core=> (Puffball. 149 "Urist")
#core.Puffball{:id 149, :name "Urist"}
core=> (apply Puffball. [149 "Urist"])
CompilerException java.lang.RuntimeException: java.lang.ClassNotFoundException: Puffball., compiling:(NO_SOURCE_PATH:3)
core=> (apply Puffball [149 "Urist"])
ClassCastException java.lang.Class cannot be cast to clojure.lang.IFn  clojure.core/apply (core.clj:600)

如何从矢量创建马勃球？

Answer 1

在 Clojure 1.3 中，记录定义自动引入工厂函数:

Clojure 1.3.0
user=> (defrecord Puffball [id name])
user.Puffball
user=> (apply ->Puffball [149 "Urist"])
#user.Puffball{:id 149, :name "Urist"}

->Puffball 是“位置”工厂函数；还有 map->Puffball，顾名思义。