Re: From extended Pascals to Ada 95 guide

[Al Christians <achrist@easystreet.com>]

David Starner wrote:
> 
> Okay, why isn't Ada a "Wirth-style language", if Modula-3 is? They
> share more in common with each other than either does with Wirth's
> Pascal, for instance.
> 

The principal criterium is size of the language definition/reference 
manual.  Modula-3's is under 60 pages, IIRC, much smaller than Ada's.
And Wirth was some kind of advisor to the M3 design team. 

M2 and M3 are both very nice languages if you want something simpler
than Ada and don't need what they leave out.  But neither one shows
much sign of life.  If you wish you had more mainstream/affordable
commercial support for Ada, the situation is about ten times worse
working with either M2 or M3.  

All three of these languages, M2, M3, and Ada, now support generics, 
and that gives them a big advantage over Delphi for coding without doing 
aribtrary conversions between data types.  In Delphi, the generic type 
stored by the standard VCL collection classes is the Pointer, and the 
program must cast it to whatever type it really represents.  One big 
reason Borland's Pascal became popular was because it let you go
around Pascal's strict type checking, but that was years ago, and it's 
regrettable to have to routinely write code that will be checked 
for correctness at run time when there are less worrisome alternatives.

I don't believe that Wirth's versions of M2 or Pascal allowed any way
to go around the type system, and in M3, the modules that might do
so must be marked as unsafe.  Ada does allow unchecked conversions.   

Al