Re: invalidly encoded strings

Hannu Krosing wrote:
> Ühel kenal päeval, T, 2007-09-18 kell 08:08, kirjutas Andrew Dunstan:
>   
>> Tom Lane wrote:
>>     
>>> Andrew Dunstan <andrew@dunslane.net> writes:
>>>   
>>>       
>>>> Tom Lane wrote:
>>>>     
>>>>         
>>>>> What I think we'd need to have a complete solution is
>>>>>
>>>>> convert(text, name) returns bytea
>>>>> -- convert from DB encoding to arbitrary encoding
>>>>>
>>>>> convert(bytea, name, name) returns bytea
>>>>> -- convert between any two encodings
>>>>>
>>>>> convert(bytea, name) returns text
>>>>> -- convert from arbitrary encoding to DB encoding
>>>>>
>>>>> The second and third would need to do a verify step before
>>>>> converting, of course.
>>>>>       
>>>>>           
>>>> I'm wondering if we should give them disambiguating names, rather than 
>>>> call them all convert.
>>>>     
>>>>         
>>> No.  We have a function overloading system, we should use it.
>>>
>>>             
>>>   
>>>       
>> In general I agree with you.
>>
>> What's bothering me here though is that in the two argument forms, if 
>> the first argument is text the second argument is the destination 
>> encoding, but if the first argument is a bytea the second argument is 
>> the source encoding. That strikes me as likely to be quite confusing, 
>> and we might alleviate that with something like:
>>
>>   text convert_from(bytea, name)
>>   bytea convert_to(text, name)
>>     
>
> how is this fundamentally different from encode/decode functions we have
> now ?
>
>
>   

They are in effect reversed. encode() applies the named encoding to a 
bytea. convert_from() above unapplies the named encoding (i.e. converts 
the bytea to text in the database encoding).


cheers

andrew