Re: OO in Ada

["Matthew Heaney" <mheaney@on2.com>]

"Georg Bauhaus" <sb463ba@l1-hrz.uni-duisburg.de> wrote in message
news:anv27t$jrs$1@a1-hrz.uni-duisburg.de...
> Matthew Heaney <mheaney@on2.com> wrote:
> :   Push_Back (List, Item);
> :
> : then is there any question that I'm appending a new element, with the
value
> : Item, to the back of object List?
>
> From a different perspective, isn't "pushing back" different
> from "appending" in standard English?  (I'm asking this because
> I don't known English well, so I might miss something.)

They are the same thing.

The example comes from Charles, which is a library modeled in the C++ STL.
I actually considered using the name Append instead of Push_Back (this would
be more consistent with names used in Ada.Strings.*), but I went ahead and
used Push_Back, to be consistent with Pop_Back.

http://home.earthlink.net/~matthewjheaney/charles/index.html


> So, will I have to know the meaning "append" of "push_back" (as
> opposed to "push_front" for "prepend"), and infer the meaning
> from the context (List, Item)? Or from Stepanov's (and Musser's?)
> popular (and standardized, so there...) wording?

The name is identical to the STL, so if you understand what

   list.push_back(item);

means, then it should be obvious what

   Push_Back (List, Item)

means, too.


> That is to say, shouldn't there be an "onto" part or similar
> in the Push_Back?

There is a tradition in Ada that the first parameter of a primitive
operation of a user-defined type be the "target" of the operation, that's
why the Push_Back operation has the parameter order it does.

For example, if I see this:

   Write (File, Item);

then it seems obvious (to me) that the operation is writing Item to the file
object File.