Groovy里面闭包中变量符号的查找与变量定义的限制

 class a {
     def v1 = "v1 in a"
     static def v2 = "v2 in a"
     def v4 = "v4 in a"
     def v5 = "v5 in a"
     def va = "va in a"
     def b() {
         def v1 = "v1 in a.b()"
         def v2 = "v2 in a.b()"
         def v4 = "v4 in a.b()"
         def g = {
             def v0 = "v0 in closure g"
             def h = {
                 //function b里面已经定义v4 = "v4 in a.b()"所以下面这行
                 //报错:The current scope already contains a variable of the name v4
                 //def v4 = "v4 in closure h"
             }
         }
         def c = {
             //下面的这行代码报错:The current scope already contains a variable of the name v1
             //def v1 = "v1 in closure c"
             println v1
             println owner
             println this
             //下面这行定义v5变量正常,输出的结果也是:v5 in closure c
             def v5 = "v5 in closure c"
             println  v5//v4
             println va
         }
         println "***" + c.toString() + "***"
         c()

        return "b func"
     }

     def d = {
         println v1;
         println v2;
         println v4;
         def v5 = "v5 in closure d"
         println v5
     }

     def e = {
         def v1 = "v1 in closure e"
         def f = {
             //下面这行代码报错:The current scope already contains a variable of the name v1
             //def v1 = "v1 in closure f"
             println v1

             //下面这行就没错,因为闭包e的v2是在后面定义的
             def v2 = "v2 in closure f"

             //下面这行报错,v3在f里面不可见
             //println v3

             def vf = "vf in closure f"
         }
         f()
         def v2 = "v2 in closure e"
         def v3 = "v3 in closure e"

         //在闭包e里面vf不可见
         //println vf
     }
 }
 def test(x) {
     println "func test start --- x:" + x
     def v1 = 1000
     def v2 = 2000
     def v3 = 3000

     x()
     println "func test--- end:"
 }
 test(new a().d)
 println "--------------"
 //println new a().v4
 println new a().b()
 new a().e()

 /*
 通过上面的测试代码可以看出:
 1.在闭包a里面定义的闭包b,那么b中定义的变量不能和和闭包a里面定义的变量名字相同.
 2.在函数a里面定义的闭包b,那么b中定义的变量不能和和函数a里面定义的变量名字相同.
 3.由此也可以推导出:在函数a里面定义闭包b,在闭包b里面定义闭包c,那么c中定义
 的变量也不能和函数a中定义的变量名字相同,对于任意多层闭包嵌套也是如此
 在闭包里面的符号查找方面:
     首先在闭包里面查找,如果闭包里面没有定义,则有两种情况(假设delegate策略是Closure.OWNER_FIRST,其它策略是一样的):
         1.如果这个闭包的外层是函数,则现在函数里面查找,如果函数里面也没有定义,则进入delegate策略即在owner里面查找,
         如果owner里面没有,则在delegate里面查找,ruguo delegate里面没有就报错
         2.如果这个闭包没外层不是函数,则直接进入delegate策略即在owner里面查找,如果owner里面没有,则在delegate里面查找
         如果delegate里面没有就报错.

 */