Itcl-自动调用析构函数并结束程序

Question

我在Itcl中编写了以下代码，当我使用eclipse IDE对其进行调试时，我看到程序正在创建SystemNode的实例，并且在删除此已创建的SystemNode之后，程序结束了（这意味着没有对“ SystemNode s”之后的行的任何调用） 为什么会这样，我该如何解决？

我的代码：

package require Itcl
namespace import ::itcl::*

class Node {

    protected variable _type ""
    protected variable _parent ""

    constructor {type} { 
        set _type $type
    }
    destructor {}

    public method type {} {
        return $_type
    }


    protected method parent {pobj} {
        set _parent $pobj
    }
}


class SystemNode {
    inherit Node

    private variable _lclusters ""
    private variable _lbundles ""


    private method clear {} {
        if { $_lclusters != "" } {
            eval delete object $_lclusters
        } 
        if { $_lbundles != "" } {
            eval delete object $_lbundles
        }
        set _lclusters ""
        set _lbundles ""
    }

    constructor {} {
        Node::constructor "system"  
    } {
        puts "done"
    }

    destructor { 
        clear
    }   

    public method addCluster {cluster} {
        $cluster parent $this
        lappend _lclusters
    }

    public method addBundle {bundle} {
        $bundle parent $this
        lappend _lbundles
    }

    public method getCluster {ID} {
            if { [expr {$ID < 0}] } {
                return ""
            } 
        if { [expr {$ID > [llength $_lclusters] }] } {
            return ""
        }
        set index $ID-1
        return [lindex $_lclusters $index]
    }

    public method getBundle {ID} {
        if { [expr {$ID < 0}] } {
            return ""
        } 
        if { [expr {$ID > [llength $_lbundles] }] } {
            return ""
        }
        set index $ID-1
        return [lindex $_lbundles $index]
    }

    public method deleteCluster {ID} {
            set index $ID-1
            set temp [lindex $_lclusters $index]
        if {$temp != ""} {  
            eval delete object $temp
            set _lclusters [lreplace $_lclusters $index $index]
        }
    }

    public method deleteBundle {ID} {
        set index $ID-1
        set temp [lindex $_lbundles $index]
        if {$temp != ""} {  
            eval delete object $temp
            set _lbundles [lreplace $_lbundles $index $index]
        }
    }
}



class ClusterNode {
    inherit Node

    private variable _lbundles ""


    private method clear {} {
        if { $_lbundles != "" } {
            eval delete object $_lbundles
        }
        set _lbundles ""
    }

    constructor {} {
        Node::constructor "cluster"
    } {}
    destructor { 
        clear
    }   


    public method addBundle {bundle} {
        $bundle parent $this
        lappend _lbundles
    }
    public method getBundle {ID} {
        if { [expr {$ID < 0}] } {
            return ""
        } 
        if { [expr {$ID > [llength $_lbundles] }] } {
            return ""
        }
        set index $ID-1
        return [lindex $_lbundles $index]
    }
    public method deleteBundle {ID} {
        set index $ID-1
        set temp [lindex $_lbundles $index]
        if { $temp != "" } {    
            eval delete object $temp
            set _lbundles [lreplace $_lbundles $index $index]
        }
    }
}

class BundleNode {
    inherit Node

    private variable _lports ""

    private method clear {} {
        if { $_lports != "" } {
            eval delete object $_lports
        }
        set _lports ""
    }

    constructor {} {
        Node::constructor "bundle"
    } {}

    destructor { 
        clear
    }   


    public method addPort {port} {
        $port parent $this
        lappend _lports
    }
}


SystemNode s   
ClusterNode c
s addCluster c