Re: Dec Ada

[Ken Garlington <garlingtonke@lmtas.lmco.com>]

John Paul Ross wrote:
> 
> I have recently started using Ada 83 on Dec Alphas. and have noticed a
> couple of changes to the normal LRM I am used to using - notably
> in the section which describes Calendar part of which seems to have
> been split into two sub-paragraphs.
> 
> Does anyone know the situation regarding this -which "version" of the
> LRM should validated compilers comply with - Dec's is dated 1993?
> 
> I am not sure whether the LRM has been changed or whether Dec have
> changed it for their own purposes can anyone enlighten me?

Yes and no. The DEC Ada compiler, as far as I know, conforms to the
1983 Ada standard from ANSI/ISO, and has passed the validation suite for 
that standard.

However, there is a DEC document that comes out with its VAX/VMS 
compiler called "VAX Ada Language Reference Manual." My hardcopy version 
is dated May 1989. I assume you received a similar manual (hardcopy or 
softcopy) from DEC for the Alpha compiler. The cover page says this:

  "This manual represents the Digital-supplemented text of ANSI/
  MIL-STD-1815A-1983, Reference Manual for the Ada Programming
  Language. Textual insertions (printed in color) describe the
  Digital implementation of implementation-dependent language
  features, as well as allowed implementation-specific additions
  to the language (pragmas, attributes, input-output features, and
  so on.)"

DEC kept the overall structure of the Ada standard in terms of paragraph 
numbers, etc. and added their own subparagraphs as needed. For example, 
paragraph 13.7 is the description of package System, as it is written in 
the Ada standard. Section 13.7a is the VAX Ada-specific additions to 
package System. To be a validated compiler, DEC has to comply to 13.7. 
However, the standard validation suite will not test for the additional 
features described in 13.7a.

If you want to write code that is strictly portable, you should use the 
Ada standard and not the DEC Ada LRM. (Note that the DEC compiler has an 
option to flag the use of non-portable constructs in the code, as well). 
However, if you want to use the full power of the DEC Ada compiler, you 
need the DEC Ada LRM.

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