The Right Approach to Exceptions

[Andrei Alexandrescu]

On 2/19/12 8:54 AM, Jacob Carlborg wrote:
> On 2012-02-19 13:27, Juan Manuel Cabo wrote:
>> How about adding a string[string] or a variant[string] to the Exception
>> class, so one can know details about the subclassed exception without
>> downcasting? How ugly would that be?
>>
>> For instance:
>>
>> ...
>> catch (Exception ex) {
>> if ("transient" in ex.details) {
>> repeatOneMoreTime();
>> }
>> if ("i18n_code" in ex.details) {
>> log(translate(ex.details["i18n_code"]));
>> }
>> }
>> ...
>>
>> Details can be standard by convention or otherwise custom.
>> (I can see that this can lead to messy proliferation of details, but at
>> least solves most of the issues).
>
> How would you know which keys are available in "ex.details", documentation?

Programmatically, too. A string templating engine would take the table 
and format it for the appropriate language.

Andrei