Thanks for the reply.
> what do you return when you do not find the class
I guess you are talking about this block: "[ self objSuperclassId ifNotNil: [ self objSuperclass lookup: selector ]]". This code is based on the assumption that the entire block returns "nil" when "self objSuperclassId" is "nil". I'm going to check if my assumption was right.
- Edouard 


    On Thursday, November 19, 2015 8:17 PM, stepharo <stepharo@free.fr> wrote:
 

  Hi edouard 
 
 I will check as soon as I get some time. 
 
  I'm new on this mailing list, this is my first mail :-)  
 welcome
 
 
  I'm a student from University of Lille (France). I'm studying this tutorial (I'm using Pharo 4 but it seems not to be a problem): http://sdmeta.gforge.inria.fr/Teaching/ObjVLisp/ObjV.pillar.pdf. I'm working with the "ObjVLispSkeleton-StephaneDucasse.1" image loaded from this repository: 
  
 MCSmalltalkhubRepository  owner: 'StephaneDucasse'  project: 'ObjVLispSkeleton'  user: ''  password: '' 
 
  I'm stuck at "Method Lookup" p11. First, it seems that unit tests "testNilWhenErrorInLookup" and "testRaisesErrorSendWhenErrorInLookup" are not provided,   
 Mark if you read this mail. Did you get problem when you did it?
 
 
  thus I'm not sure that I'm working with the right image (everything was fine until p11 though). Then, the "lookup: selector" is not provided neither.   
 
 Not providing lookup: is ok since you have to define it. I will look for the tests in my version. 
 
 
  While there is another method named "lookup: selector from: anObjObject", I can't figure out what I'm supposed to do with the second parameter.   
 What you should see is that the second argument is is provided here because when you raise an error, you should send a messageNotUnderstood 
 and this message should be sent to the original object that received the message and not the class where the method was found. 
 So lookup will use the receiver to walk through the inheritance chain and the from: argument in case of error
 
 
 
 
  Here is what I would do: 
  
 lookup: selector  "look for the method named <selector> starting in the receiver.   The lookup is done for a message sent to <anObjObject>. self is an objClass"  ^ self objMethodDict  at: selector  ifAbsent: [ self objSuperclassId ifNotNil: [ self objSuperclass lookup: selector ] ] 
  
 what do you return when you do not find the class
 
 
 
  
  Could someone tell me if this implementation is correct? If it's correct, what do you think the second parameter is for?  
  Moreover, do you think I'm working with the right image? 
  Thanks. 
  - Edouard  
 
 

  

Hi, I found "testNilWhenErrorInLookup" indeed, sorry for that. "testRaisesErrorSendWhenErrorInLookup" is still missing though. Maybe the name has changed to this one: testMethodNotFoundRaiseError "(self  run: #testMethodNotFoundRaiseError)" self should: [aPoint unarySend: #zork] raise: Error. About the lookup method, I should not use "lookup: selector from: anObjObject" at all right? - Edouard On Thursday, November 19, 2015 8:24 PM, stepharo <stepharo@free.fr> wrote: I checked testNilWhenErrorInLookup     "(self  selector: #testNilWhenErrorInLookup) run"         self assert: (pointClass lookup: #zork) isNil.     "The method zork is NOT implement on pointClass"     testRaisesErrorSendWhenErrorInLookup     "(self  selector: #testRaisesErrorSendWhenErrorInLookup) run"         self should: [  pointClass send: #zork withArguments: { aPoint } ] raise: Error.     "Open a Transcript to see the message trace" Le 19/11/15 13:50, Edouard Delbar a écrit : Hello everyone, I'm new on this mailing list, this is my first mail :-) I'm a student from University of Lille (France). I'm studying this tutorial (I'm using Pharo 4 but it seems not to be a problem): http://sdmeta.gforge.inria.fr/Teaching/ObjVLisp/ObjV.pillar.pdf. I'm working with the "ObjVLispSkeleton-StephaneDucasse.1" image loaded from this repository: MCSmalltalkhubRepository owner: 'StephaneDucasse' project: 'ObjVLispSkeleton' user: '' password: '' I'm stuck at "Method Lookup" p11. First, it seems that unit tests "testNilWhenErrorInLookup" and "testRaisesErrorSendWhenErrorInLookup" are not provided, thus I'm not sure that I'm working with the right image (everything was fine until p11 though). Then, the "lookup: selector" is not provided neither. While there is another method named "lookup: selector from: anObjObject", I can't figure out what I'm supposed to do with the second parameter. Ok I checked in the other method is old the new one should be lookup: selector     "look for the method named <selector> starting in the receiver.     The lookup is done for a message sent to <anObjObject>. self is an objClass"     Here is what I would do: lookup: selector "look for the method named <selector> starting in the receiver.  The lookup is done for a message sent to <anObjObject>. self is an objClass" ^ self objMethodDict at: selector ifAbsent: [ self objSuperclassId ifNotNil: [ self objSuperclass lookup: selector ] ] Could someone tell me if this implementation is correct? If it's correct, what do you think the second parameter is for?  Moreover, do you think I'm working with the right image? Thanks. - Edouard