Re: Building blocks (Was: Design By Contract)

[Alan E & Carmel J Brain <aebrain@dynamite.com.au>]

W. Wesley Groleau x4923 wrote:
> 
> > Yes, it's quite wrong to use a flag to terminate a while loop,
> > instead of just using exit with a loop.  The idiom is, use an
> > exit when the termination depends on what you read, .....
> 
> Or to end a search when the item is found, or ...
> 
> Unfortunately, there are those who feel that not identifying the
> loop termination at the beginning of the loop confuses the reader.
> These folk are supported by a non-thoughtful reading of Ada Quality
> and Style.  The "guidelines" (we all know that's another word for
> "rules," right?) say to only exit from a plain loop, never from
> a 'while' or 'for'  So folks go through wierd contortions to avoid
> "exit."  But the accompanying explanation clearly says that
> _readability_ is the criteria for choosing a loop construct.

Concur. The "bottom line" is readability, that's a given (I hope..). In
this case, W. Wesley Groleau has provided pursuasive evidence that my
"while Unfinished" construct is less readable than his "exit" construct.
Although I'm not completely convinced, I am pursuaded that the "exit"
construct is superior, at least in this case. 

And I thought I was a true disciple of "egoless" review. There's nothing
like having a bunch of people expose one's coding failings in public,
calmly and correctly, to show how far one has to go. Still, I've learnt
something important I didn't know before, and that's worth any amount of
ego damage. My thanks to all concerned.
 
-- 
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