Experimental Physics and
Industrial Control System

"Jeff Hill" <[email protected]> · Wed, 28 Sep 2005 09:06:22 -0600

I suppose that these operations *are* constant time given that there
execution time has a linear relation with the number of properties in the
container.

That same relation exists for other compound types like Rational (whose
assignment operator takes two times longer because there are two datums).

Jeff

> -----Original Message-----
> From: Kay-Uwe Kasemir [mailto:[email protected]]
> Sent: Tuesday, September 27, 2005 1:18 PM
> To: [email protected]
> Subject: Re: data access structures, strings
> 
> Hi:
> On Sep 27, 2005, at 14:47 , Jeff Hill wrote:
> > PropertyCatalog currently has "operator =" and "operator ==".
> >
> > O Do they meet the conventional wisdom test? That is, is their purpose
> > roughly equivalent to the purpose of these operators with primitive
> > types?
> 
> The '=' is supposed to be a simple assignment.
> Something that can usually be done in one machine-code instruction.
> Maybe a memcpy or double-to-int conversion.
> Not invocations of traverse(), looking for matching properties
> via find(), converting types, ...
> Such a rather complex mapping exceeds what I'd expect
> behind a simple '='.
> 
> I think "The C++ Programming language" has a discussion
> for iterators, operator ++.
> If it's a constant-speed iteration, like an in-memory linked list:
> OK.
> Not OK for remote database access where one '++' returns immediately,
> the next one takes a minute.
> 
> 
> -Kay

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System