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From: "Per Dalgas Jakobsen" <i@hate.spam>
Newsgroups: comp.lang.ada
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Subject: Re: Improving Ada's image - Was: 7E7 Flight Controls Electronics
Date: Tue, 1 Jun 2004 23:14:11 +0200
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Date: 2004-06-01T23:14:11+02:00
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>> *) that the reusability factor of Ada is magnitudes higher than for
C/C++.
>
> Really? Why do you think so? What is it about Ada that would make a body
> of code written for one purpose reusable for another, in a way that does
> not apply to C or C++?

Reusability implies portability (at least for my case), since we are using
several platforms for a given system.
Generics/templates aids reusability


For generics/templates:

For C it gives itself: no generics/templates. You could use macros for some,
but they really doesn't do the job very nice.

For C++, templates should be the answer, but unfortunately quite a bit of
"implementation specific freedom" renders this feature "less useful".
http://www.mozilla.org/hacking/portable-cpp.html (a bit old, but still valid
to some extend).

For Ada, generics seems to work quite nicely.


For portability:

C and C++: I would almost call it non-existing. Try reading a binary
byte-aligned file into a C/C++ struct. It's fairly easy with one compiler
(if it's not the opposite endianess), but try make it work across different
compilers... :-(

Ada has the nice for-use statement that pretty much solves this mess.


And just exactly how big is an int? Well, we could define an int16 for a
signed 16 bit integer, int32 ..., etc. But how do you get it into your code:
You include a header-file with sized integer types.
Then another guy wants to use your code, but he has his own header-file with
sized integer types, unfortunately this guy has named his unsigned 8 bit as
uchar8, and you called it uint8. Now what? Things gets very messy, very
fast.

In Ada you just define a type with a suitable range and size.


C and C++ has conditional compiles, which very fast gets very messy.

No such thing in Ada.


I believe we could add quite a bit to this list.
Btw.: "Safer C" by Les Hatton is "fascinating" reading.


Did I miss the point here?

Per