Re: Flexible Strings (was Equality operator...)

["W. Wesley Groleau (Wes)" <wwgrol@PSESERV3.FW.HAC.COM>]

(Also posted to comp.lang.ada)

:> >I never had a problem implementing an Ada-83 equivalent of bounded strings
:> >so that no heap was required.  Did it pretty much as Matt Heaney suggested,
:> >after reviewing a couple of "free" dynamic_strings packages and finding
:> >that nearly every operation leaked heap.
:>
:> The problem with Ada 83 is that when you do need it, memory leaks are bound
:> to happen, because clients often forget to clean up the data structure.

The problem with the packages I was offered was that the clients COULDN'T
clean up the heap.  These guys had every string on the heap, and if a client
wanted to say A := A & B the result was a new allocation overwriting the
previous pointer in A.

:> I got the "+" idea from Barnes' book.  Don't think of it as a hack; think
:> of it as what it is: the identity operator.  It's a happy medium between
:> the 2 extremes.

I agree with you that automatic conversion is generally harmful.  And that
too much explicit conversion is information hiding of the wrong sort, i.e.,
hiding the abstraction in implementation clutter.  The thing with "+" is
more an issue of retraining one's instincts--after more than 35 years, it's
hard not to think of it as something associated with quantities.  But then,
the strangeness of it is a point in its favor because it catches the
attention.  If it were routine, being only a single character, it could
easily be overlooked.

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W. Wesley Groleau (Wes)                                Office: 219-429-4923
Hughes Defense Communications (MS 10-41)                 Home: 219-471-7206
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