Re: PostgreSQL port to pure Java?

My 2 cents...



The C++ language is a horrible language from an OO perspective. Operator
overloading, copy-constructors, templates, etc. can produce quite horrendous
and inefficient results if used incorrectly. Having said that I must defend
it some too.



Using C++, you get inheritance, data-hiding, polymorphism, and namespaces.
None of that is present in C. When used correctly, those mechanisms help
greatly when creating safe, reusable, and pluggable code. Code that will
become less error-prone than C code simply because it very effectively
inhibits a huge number of errors that can (and almost always are) found in C
code.



No language provides magic pluggability in itself. But a language that
supports OO semantics is a much better fit when such logic are designed than
a language that doesn't. Pluggability implies interfaces. Interfaces are not
intuitively created in C.



I've been involved in quite huge C++ projects myself. One of the projects
was actually to write an Object Oriented Operating System (embedded on M68K
boards). C++ is excellent for this and I imagine the same would be true when
writing a DB-engine. Some restrictions should be applied to make C++
"housebroken" such as:



1. Pass everything by pointer, never by &ref. This prevents accidental
execution of copy-constructors.

2. Never ever allow operator overloading. Use true methods instead. Using
op-overloading, the code might look elegant at first but after a while it
degenerates and gets hard to undersand.

3. Refrain from macros as much as possible (it makes the code hard to
understand and hard to debug.) Create inline methods instead if performance
is an issue. Compare to Java where you actually have no preprocessor
capabilities whatsoever.

4. Use templates very selectively, if indeed ever.

5. Have everything inherit from one common Object (so that collections etc.
store a base type).



- thomas



-----Original Message-----

From: pgsql-hackers-owner@postgresql.org
[mailto:pgsql-hackers-owner@postgresql.org] On Behalf Of Doug McNaught

Sent: Thursday, December 11, 2003 15:24

To: Shridhar Daithankar

Cc: Postgresql Hackers

Subject: Re: [HACKERS] PostgreSQL port to pure Java?



Shridhar Daithankar <shridhar_daithankar@myrealbox.com> writes:



> Jokes and facts aside, I can't help it to think how better it would

> have been, if postgresql was in C++. We could easily plug multiple

> implementations of underlying subsystems without mucking much in base

> code..



That's easy to do in any language if your code is carefully designed

for it (look at the Linux kernel for an example in C) and hard to do

even in C++, if the design isn't suited.  So your assertion that C++

would have magically enabled "pluggabilty" doesn't hold water.



>   Wild thought anyways..



Indeed.



-Doug



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"Doug McNaught" <doug@mcnaught.org> wrote in message
news:87n09zqvph.fsf@asmodeus.mcnaught.org...
> Shridhar Daithankar <shridhar_daithankar@myrealbox.com> writes:
>
> > Jokes and facts aside, I can't help it to think how better it would
> > have been, if postgresql was in C++. We could easily plug multiple
> > implementations of underlying subsystems without mucking much in base
> > code..
>
> That's easy to do in any language if your code is carefully designed
> for it (look at the Linux kernel for an example in C) and hard to do
> even in C++, if the design isn't suited.  So your assertion that C++
> would have magically enabled "pluggabilty" doesn't hold water.
>
> >   Wild thought anyways..
>
> Indeed.
>
> -Doug
>
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> TIP 5: Have you checked our extensive FAQ?
>
>                http://www.postgresql.org/docs/faqs/FAQ.html
>