Re: Why Ada is not the Commercial Lang of Choice

[donh@syd.csa.com.au (Don Harrison)]

I wrote:

:> However, they differ in that digits must be grouped in threes. Grouping in 
:> threes is an arbitrary choice and, IMO, too restrictive. For example, it makes 
:> no sense for base 2 literals. OTOH, I think Ada's free placement is too liberal 
:> because it allows different groupings within the same literal.
:> 
:> Something in between is probably optimal - like allowing any grouping but with
:> the restriction that it must be consistent within a literal.

Two situations have been suggested where free placement would be desirable:

  a) Use of numbers for identity, and
  b) Binary representations with different boundaries.


Larry Kilgallen wrote:

:I can envision an application using part numbers, where the first
:two digits indicate the plant that built the part  and the last
:two represent the revision number. In that case, 21_302_561_03
:might be a much more natural representation than 2_130_256_103.
:In fact, absent some other well-known (to humans) aspect of the
:part numbering scheme, it would also provide a better scanning
:profile than 21_30_25_61_03.

Maybe a better way of indicating identity would be to use a class PART_NUMBER 
containing the various sub-components and use strings for I/O. If you use
integers, you get unwanted arithmetic operations that are inappropriate for 
part numbers.


Donovan Baarda wrote:

:Nahh, why limit things? Arbitary placement of underscores is handy when
:you want to define an integer literal bit-field where bits are clustered
:on arbitary boundarys.

True.


Roy Grimm wrote:

:I like having the freedom to place underscores where I need them.  In
:some of the work I do, I have to break up and assemble 32 bit words
:composed of varying segments.  I like having the ability to use a mask
:that looks like this:
:
:2#0_00_00000_1111111111111111_00000000#
:
:On the other hand, the same incoming bus data can be masked as so:
:
:2#0_00_1111111_1111111_1111111_00000000#
:
:In this case, having the flexibility is really nice.  I guess it really
:has to do with the context of the job you're doing.

Agree. I suspect the only situations where you would need the flexibility is
for binary representations. Otherwise, regular placement should suffice.
 

Don.
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Don Harrison             donh@syd.csa.com.au