new Smalltalk programmer's thoughts
ducasse at iam.unibe.ch
Sat May 6 18:42:18 UTC 2006
> But the changes I'd need in this case are reaching too far.
> They'd include:
> - Upper bounds of integer intervals are exclusive and lower bounds
> - Index ranges start at zero
> - The positions of Positionable Streams would take the same values as
> the indexed variables of their underlying collections.
> With theses changes predicates involving indexes and positions get
> more elegant.
> This in turn lessens the burden you face when formulating
> specifications of
> methods and reasoning about methods to prove that they meet the
> This in turn is the only technique I know of that saves you from
> "off by one"
> errors in particular and "bugs" in general.
> So the changes *are* important.
> And hard to implement in Smalltalk.
> Or, viewed as biological species, Squeak and even Smalltalk-80
> evolved to a
> level where they lost the flexibility to meet the "new" challenge
> of switching
> from the dark art of medieval metaphors to the scientific technique
> of logical
This is clear that I was thinking about gemstone possibility of
versions at the same time as a way to support a muc smoother evolution.
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