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From: markm@cs.qmc.ac.uk (Mark Magennis)
Newsgroups: comp.lang.smalltalk
Subject: Re: Adding instance variables to Sm/V classes
Message-ID: <1177@sequent.cs.qmc.ac.uk>
Date: 3 Aug 89 13:32:35 GMT
References: <1174@sequent.cs.qmc.ac.uk> <1176@sequent.cs.qmc.ac.uk>
Reply-To: markm@cs.qmc.ac.uk (Mark Magennis)
Organization: Computer Science Dept, Queen Mary College, University of London, UK.
Lines: 88
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How embarrasing, sorry.

I'm afraid the previous message I sent on this subject was
completely wrong. I copied an older and non-working method. I
can't even delete it either, it tells me that it's someone
elses message. In that case I wont take the blame :-)

Here is code that definitely works for Menu class among others,
SO FAR. That means my image hasn't fallen over yet, after a
lot of menu work.

If you want to try it please work on a spare image until you
are absolutely sure it is safe with whatever class you wish to
use it.

Again, this is for a class (Menu) without subclasses.

***************************************************************

The new method in Class, removeAndBecome: aClass is a copy of
removeFromSystem but with the two occurences of DeletedClass
changed to aClass.

|newInstance|

"Change instances of Menu into instances of NewMenu"

Menu allInstances do: [:anInstance |
    newInstance := NewMenu new.
    1 to: Menu instSize do: [:index |
        newInstance instVarAt: index
                   put: (anInstance instVarAt: index)].
    anInstance become: newInstance].

"Copy instance methods from Menu to NewMenu "

Menu selectors do: [ :each |
    NewMenu addSelector: each withMethod: (Menu compiledMethodAt: each)].

"Copy class methods from Menu to NewMenu"

Menu class selectors do: [ :each |
    NewMenu class addSelector: each
                   withMethod: (Menu class compiledMethodAt: each)].

"Copy class variable values from Menu to NewMenu"

Menu classVarNames do: [ :aClassVar |
    NewMenu classPool at: aClassVar put: (Menu classPool at: aClassVar)].

"Set the instance methods' class field to NewMenu"

Menu selectors do: [ :each |
    (Menu compiledMethodAt: each) classField: #NewMenu].

"Set the class methods' class field to NewMenu"

Menu class selectors do: [ :each |
    (Menu class compiledMethodAt: each) classField: NewMenu class].

"Copy the structure variable"

NewMenu structure: Menu structure.
NewMenu class structure: Menu class structure.

"Remove Menu, change references to become NewMenu and rename
NewMenu"

Menu removeAndBecome: NewMenu. "*A new method in Class*"
NewMenu rename: #Menu.

"Reset the instance methods' class field to Menu"

Menu selectors do: [ :each |
    (Menu compiledMethodAt: each) classField: #Menu].

"Reset the class methods' class field to Menu"

Menu class selectors do: [ :each |
    (Menu class compiledMethodAt: each) classField: Menu class].

***************************************************************

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