Re: [Firebird-devel] Parameterized Exceptions

[Vlad K. <hv...@us...>]

>>> Currently user can't create good exception texts and rely on them,
>>> because exceptions generally need more informations. So user need to
>>> throw exceptions passing its complete text [exception e1 'Exception ' ||
>>> info1 || ' at ' || info2]. This lose the ability to create exception
>>> texts and to catch the parameters without parse the formated text.
>>>
>>> The exceptions are currently encoded in this way:
>>> isc_except, <number>,
>>> isc_random, <string>
>>>
>>> I propose to make parameters directly inside user text exceptions, like
>>> this:
>>> create exception e1 'Exception @1 at @2';
>>>
>>> This is easy for user, easy for the engine. Does not need metadata
>>> extensions and is backward compatible.
>> 
>>     Why not implement built-in FORMAT function instead ?
>> 
> This does not allow the client (or even in PSQL) to catch the exception
> parameters, 

    Here i can understand and even agree :) I have a big doubt users will 
parse status-vector looking for parameters, however. They will sooner parse 
combined text message as they do now ;) But i agree, it have its own pluses.

> and to define messages right in the exception. 

    This is i don't understand.

> FORMAT is useful, and should format the same way exceptions are formated, 

    Agreed.

Regards,
Vlad

PS I think we should not use isc_random with such messages and tweak the engine.

PPS How do you going to handle case when passed arguments not corresponds to the
    placeholders in text message ?