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From: Rod Kay <rodakay5@gmail.com>
Newsgroups: comp.lang.ada
Subject: Re: Extra information in the message string of exceptions.
Date: Tue, 7 Jun 2022 21:47:38 +1000
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On 7/6/22 12:33, Randy Brukardt wrote:
> 
> Janus/Ada has *always* done this (going all the way back to the original
> Z-80 CP/M compiler).

    Very nice !

  This particular case is not very expensive, since one
> can use the fact that the out-of-range value is certainly in a register to
> be tested in order to construct the message. And no real program cares about
> the performance of raising Constraint_Error

    I didn't think that there would be too much impact on performance.


  -- the main issue is one of
> space (making the program larger).
> 
    I hadn't really considered the extra space required. For a 
desktop/workstation/server, I expect the extra space would not be a huge 
consideration. For embedded systems and such, I guess it might be, 
though if the feature could be switched off for production releases 
perhaps not such a big problem.



> P.S. I'd quibble with the OP, in that the vast majority of Constraint_Errors
> have nothing to do with the standard library; their checks are compiled
> directly into the code of your application.

    Quite right. I should simply have said the standard exceptions, 
wherever they are raised.