Class hierarchy problem

[Gérard Bunel]

Hi James,

palying around redline I tried the following code:

| cls |

cls := Class.

[cls == nil]

  whileFalse:

    [

      Transcript cr; show: cls.

      cls := cls superclass.

    ]

This code fails as follow:

Class

ClassDescription

Behavior

Object

ProtoObjectException in thread "main" java.lang.NullPointerException

at st.redline.core.PrimObject.perform0(PrimObject.java:774)

at st.redline.core.PrimObject.perform0(PrimObject.java:760)

at st.redline.core.PrimObject.perform(PrimObject.java:716)

while, using Pharo, it produces the following output:

Class

ClassDescription

Behavior

Object

ProtoObject

I looked at Bootstrapper As I suspected a maybe not Nil superclass on ProtoObject. But I see that:

        PrimObjectMetaclass protoObjectClass = protoObjectMetaclass.basicCreate("ProtoObject", PrimObject.PRIM_NIL, "", "", "", "");

Which seems correct to me. So, I don't understand!!

Any advice ?

Gérard

[James Ladd]

I suspect the problem is because Nil hasn't got a superclass set.

Ill look into it

Sent from Hyperspace.

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[Gérard Bunel]

Hi James,

Could you explain the differences between PrimObject.NIL and PrimObject.PRIM_NIL.

What's the purpose of PRIM_NIL?

Gérard

[James Ladd]

Nil is the object and prim_nil is the primitive - during bootstrap prim_nil is used and after nil

Sent from Hyperspace.