Re: Running a preprocessor from GPS?

["Jeffrey R. Carter" <spam.jrcarter.not@spam.not.acm.org>]

On 08/01/2015 05:19 AM, EGarrulo wrote:
> 
> But the original point was that the Singleton pattern was conceived to work
> around deficiencies in the languages used in the "Design Patterns" book.  I
> don't see how those languages are deficient in that respect.  It is just that
> those languages implement the concept differently.  What is a package in Ada,
> is a class with static methods in C++ and Java, or even a ".c" file in C.  The 
> goal of the "Design Patterns" book was not to describe how to work around 
> deficiencies in a language, or even to show how to solve some design problems, but to describe but how problems had already been solved and then to establish
> a shared vocabulary to improve communication between designers.  The "Design 
> Patterns" book is descriptive, not prescriptive.

I guess we have different definitions of "deficiency." Yours seems to be
something that it is impossible to achieve using the language; if there's a way
to do it, no matter how difficult, complex, and unintuitive, then it's not a
deficiency. By mine, a language that doesn't have a simple, obvious way to
implement common concepts has a deficiency.

In this case, a common idiom that is so simple and obvious in Ada that it
doesn't even have a name for it (I was creating them for over a decade before I
ever encountered the term "singleton" as used in DP) is so difficult, complex,
and unintuitive in these other languages that apparently many people can't
figure it out on their own, so the "trick" has to be written down for them.

The differences between true modules and the C++ "class" construct have been
hashed over so much that there's no point in me repeating it here. The upshot of
it is that they are not equivalent. If they were, a singleton in C++ would be as
simple and obvious as in Ada.

The pkg is a very important concept in Ada, and your insistence that there has
to be a Get_Instance function shows that you don't fully understand it yet.
Until you do, you won't really understand Ada.

-- 
Jeff Carter
"I don't know why I ever come in here. The
flies get the best of everything."
Never Give a Sucker an Even Break
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