[Oberon] n-o trap analysis confuses me
easlab at absamail.co.za
easlab at absamail.co.za
Sat Mar 27 10:00:15 CET 2004
cg> Using Compiler.Compile *\f
on PC = PC = 7583 & 5551
Peter wrote:
> Is this the trap from the gif image?
>
Well since I can't produce the trap now; which I had repeatedly done
over months, for different re-boots; and all I have as evidence is
the old trap-text, I must assume the 2 PCs were where it WAS
trapping. And that the traps WERE initiated by some graphic
input.
> Otherwise, can you narrow down the html
> source to where you understand what is
> instigating the problem?
I never ever suspected that there was anything 'wrong'
with the fetched graphics. The problem is at my end and
most likely with ME. When I read the source, I [obviously
mistakenly] see this simplified pattern:---
PROCEDURE Outer;
VAR C: INTEGER;
PROCEDURE Inner(arg1: CHAR; arg2: INTEGER);
BEGIN
ReadVariable(C);
END ImgIcon;
BEGIN (* Outer *)
Inner("X", 2);
Acces(C);
PossiblyInitialise(C)
END IMG;
My reasoning is that:
1. C must be initialised before:
ReadVariable(C); [in PROC Inner] is executed.
2. since C is local to 'Outer' and its decendants, it must be initialised
by a statement in PROC Outer, or by a call to a decendant procedure.
3. Since there is only one decendant procedure of PROC Outer,
C must be initialised either before
Inner("X", 2) [in PROC Outer] is executed, or before
ReadVariable(C) [in PROC Inner] is executed.
The range of statements where it must be initialised, is quiet
small/managable to examine in the source of HTMLImages.Mod
I can't find how/where C is initialised.
Where are the bright students, before they go on easter leave ?
== Chris Glur.
More information about the Oberon
mailing list