Re: operation can be dispatching in only one type

[Serge Robyns <serge.robyns@gmail.com>]

On Monday, 23 November 2015 14:48:45 UTC+1, Dmitry A. Kazakov  wrote:
> On Mon, 23 Nov 2015 05:05:02 -0800 (PST), Serge Robyns wrote:
> 
> > On Monday, 23 November 2015 12:29:55 UTC+1, Dmitry A. Kazakov  wrote:
> >> On Mon, 23 Nov 2015 02:23:57 -0800 (PST), Serge Robyns wrote:
> >> 
> >>> I'm facing an issue with Ada when it comes to use an operation on two
> >>> tagged types.
> >> 
> >> You can use tagged types, they cannot be dispatching arguments though. That
> >> is a big difference.
> >> 

> C++ code is broken, always broken, because C++ confuses T and T'Class and
> hence re-dispatches each time and every place (except for ctors). Ada's
> exact equivalent to
> 
> void account::update_balance (account_balance& ab, money amount)
> 
> is
> 
> procedure Update_Balance (X : in out Account;
>     AB : in out Account_Balance'Class, ...)
> 

This one did the trick.  I do feel very frustrated with regards to the Ada idiosyncrasies, if I may say so. Recalls me the "'" notation I had to use when declaring a part of a constant that was from a parent class.  I got this trick in this newsgroup too.  Trying to google on Ada "'" is a challenge :-P.

I'm wondering the best way to "learn" these without falling asleep while reading for the 10th time basic programming stuff and then missing that one important comment in the text.