RE: From extended Pascals to Ada 95 guide

["Robert C. Leif, Ph.D." <rleif@rleif.com>]

From: Bob Leif
To: Gauter, James Smith et al.

I agree on Modula. However, Wirth et al. were able to create a very elegant
operating system with Oberon. The sources in Project Oberon appear to be
more Ada like. However, I am not a language expert. I believe that persons
who propose to develop an operating system in Ada should look at the Oberon
operating system. Wirth was correct in building an operating system with
useful tools. In retrospect that is what should have been done with Ada.

-----Original Message-----
From: comp.lang.ada-admin@ada.eu.org
[mailto:comp.lang.ada-admin@ada.eu.org]On Behalf Of Gautier
Sent: Friday, August 25, 2000 4:17 AM
To: comp.lang.ada@ada.eu.org
Subject: Re: From extended Pascals to Ada 95 guide


James Smith:

> Too bad the US gov didn't save some taxpayer dollars by just adopting
Modula
> 2. Of course that would have made too much sense.

To save dollars they also could have adopted C...
With Modula-2, they should have spent perhaps more than Ada to make it
usable...

The main problem with Modula-2 is that it keeps the rigid types
of "classic" Pascal. No problem for teaching or write a
"Pascal in Pascal" compiler, but for the real world you need
a flexible typing like "array(integer range <>) of..."

The second problem is the modularity: you have to open manually
the visibility for *all* identifiers you need! It made things
easier for writing a compiler, but it rapidily took longer to
write and maintain the "FROM...IMPORT..."s, with correct casing,
than to write your programs. Just extrapolate the "Hello World"
to have an idea...

MODULE PrintHelloWorld;

FROM InOut IMPORT WriteString, WriteLn;

BEGIN
        WriteString('Hello world!');
        WriteLn;
END PrintHelloWorld.

Another big problem was the library: there were vague recommendations
for text I/O, and iirc, nothing more. As a result, even "Hello World"
was non portable: some compilers wanted "WriteString('Hello world!');",
others wanted "WRITESTRING('Hello world!');" I let you guess what the
mess was with Math libraries...

Finally I doubt that the average US programmer would have been
patient enough to stand more than 5 minutes before Modula-2...
Already in Europe many keyboards were severely damaged!

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Gautier  --  http://members.xoom.com/gdemont/gsoft.htm