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 ;) 

    As you already wrote in README.exception_handling :

    "client library older than 3.0 will not be able to correctly format exceptions 
raised in this new way".

    Therefore i ask again to at least think on [optional] ability of server-side 
formatting of such messages.

Regards,
Vlad

PS You named new error code as "isc_formatted_exception". Do you see the 
ability to use it not only for user exceptions ? I prefer to see more generic name. 
Note, this error code is used for formatted string, not for exception itself.