On Tuesday 13 March 2001 10:27, Zoran Vasiljevic wrote:
Hi !
I strongly suspect that in0.84 version, the mixin process is changed, which brings some incompatibilities.
yes, the initialization of per-object mixins changed, and it is documented in the changelog (i inserted an exclamation mark before the item to denote the potential incompatibility) and in the tutorial. i have removed now the obsolete part from the language reference and rewrote the section in the tutorial more explicit as follows: ---- Note, that the constructors (init methods) of per-object mixins (and per-class mixins) are only called, if the mixin is registered already during object initialization (when init is called). For per-object mixins, one can achieve the initialization of a mixin via an idiom like
Object o -mixin M -init
that registers the mixin before init is called. When a mixin is registered after object creation and it needs initializations, it is neccessary to define special methods for this. Note, that the behavior described here is introdoced in version 0.84 to ensure consistent behavior of intrinsic classes, per-object and per-class mixins, and to achieve predictable behavior for dynamic registration for all kind of mixins, and as well during recreations of objects having mixins registered. Older versions used heuristics for the initialisation of per-object mixins. ----
For your example below, i would recommend to use a per-class mixin "... A instmixin B" since the intension is obviously to register the mixin for each instance of Class A
hope, this clarifies best regards
-gustaf neumann
Please consider this simple example
Class A Class B
A instproc init {args} { [self] instvar C [self] mixin B
set C(Aelement) 1} B instproc init {args} { [self] instvar C set C(Belement) 1 }
A instproc foo {args} { puts "[self] A bar" } B instproc foo {args} { puts "[self] B bar" }
The 0.83 behaviour...
% A a % a foo
::a B bar
% a array get C Belement 1 Aelement 1
The 0.84 behaviour
% A a % a foo
::a B bar
% a array get C Aelement 1
WHERE is the "Belement" ?????? It seems that 0.84 does not properly calls the "init" on the B class before doing an mixin ? Or am I missing something completely? Any ideas ?
Cheer's Zoran Vasiljevic Archiware
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