Re: Ada Idioms Progress Preview

[Ted Dennison<dennison@telepath.com>]

In article <5ee5b646.0108071819.6e84e33d@posting.google.com>, Robert Dewar
says...
>
>I understand Tom's point here, and I would rephrase it as a requirement
>that Ada idiom's be obvious once seen to someone who knows Ada. That's
>true for example of Stanley's Boolean'Pos idiom (which is indeed a
>useful one to know). 
..
>It should not be:
>
>c) Gadzooks! What on earth does that mean, let me reach for the LRM.
>Ah, yes, finally figured it out -- to clever for me!

Out of curiosity, which category would you place the "Rosen Trick" in? I'd think
the latter. It might be farily clear to an Ada expert what the code does, but
without extensive commenting (or knowledge of the trick) it would be rather
tough to figure out why someone would go through all that trouble.

For those who don't know: The Rosen Trick, if I remember correctly, involves
using self-referencing access fields in a record structure to allow modifiction
of an "in" parameter. By convention, it should only be considered when the
client's view of the parameter won't change, but some internal bookeeping needs
to be done. Do a groups.google search for more info.

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