Bob Arning wrote:
>
>  On Wed, 14 Jul 1999 12:00:44 +0100 "Peter Novak" <pno at whitestein.com> wrote:
>  >sometimes I need to have a breakpoint in some critical section of code. For
>  >example in method at: ifAbsent: in SystemDictionary (Dictionary), or in some
>  >method in class Class (like is scopehas: ifTrue:). I think that it's clear
>  >that it's a madness to do something like this, because every time I tried to
>  >evaluate something (anything), the system crashed, or went into the
>  >unuseable state.
>
>  Some ideas: 1) have the debugging code be very selective about when
>  it happens (just once, e.g. or only when certain peculiar conditions
>  exist), 2) have it do something
>  simple like add an element to an OrderedCollection instead of halting
>  and 3) be prepared for things to crash - file out the pertinent code
>  just before you make the last connection so you don't have to reinvent
>  everything the next time.

Thans. It seems to me to be a better idea to add an element to a
Collection
than "Smalltalk halt".

>
>  ...
>
>  >And I have another question. How is possible to recompile class
>  >SystemDictionary (exactly if I want to add method at: ifAbsent: to class
>  >SystemDictionary) ??? It is little bit dangerous to make such things, but I
>  >need it.
>
>  Adding a method does not cause the class to be recompiled. Adding 
>an instance _variable_ does.
>
>  >So I think that you, old smalltalkers, have maybe some methods to go around
>  >these problems. Can someone give me an advice??? Or in another form: How can
>  >I safely rewrite some of kernel classes of Smalltalk???
>  >
>
>  A more specific example would help here (privately, perhaps, given 
>the current level of discussion on the list).

Okay. Exactly I tried to add a class X. It's superclass was Dictionary
and one of
its subclasses was SystemDictionary. Class SystemDictionary automaticaly
recompiles
when I try to change its superclass. Everything could be okay, but class
X had defined
method at: ifAbsent: which is used by Smalltalk (uses at: ifAbsent: from
class
Dictionary). This is my problem and reason for searching for someone who
os able
to solve my problem faster than me ;).

peter.
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