Re: proposal: UTF8 to_ascii function

2008/8/11 Andrew Dunstan <andrew(at)dunslane(dot)net>:
>
>
> Jan Urbański wrote:
>>
>> Andrew Dunstan wrote:
>>>
>>>
>>> Pavel Stehule wrote:
>>>>
>>>>
>>>> One note - convert_to is correct. But we have to use to_ascii without
>>>> decode functions. It has same behave - convert from bytea to text.
>>>> Text in "incorrect" encoding is dafacto bytea. So correct to_ascii
>>>> function prototypes are:
>>>>
>>>> to_ascii(text)
>>>> to_ascii(bytea, integer);
>>>> to_ascii(bytea, name);
>>>>
>>>>
>>>>>
>>>>>
>>>
>>> What you have not said is how you propose to convert UTF8 to ASCII.
>>>
>>> Currently to_ascii() converts a small number of single byte charsets to
>>> ASCII by folding the chars with high bits set, so what we get is a pure
>>> ASCII result which is safe in any server encoding, as they are all ASCII
>>> supersets.
>>>
>>> But what conversion rule will you use for the gazillions of Unicode
>>> characters?
>>>
>>> I honestly do not understand the use case for this at all.
>>
>> I do. Often clients want their searches to be
>> accented-or-language-specific letters insensitive. So searching for 'łódź'
>> returns 'lodz'. So the use case is there (in fact, the lack of such facility
>> made me consider not upgrading particular client to 8.3...).
>> Or maybe there's a better way to do it?
>
> Well, my first question would be "Why aren't you using a database encoding
> that supports to_ascii()?"
>
> However, I suppose that your use case would support this signature:
>
> to_ascii(bytea, name)
>
> where it would just error out if the encoding name were something other than
> LATIN1, LATIN2, LATIN9, or WIN1250.
>
> But what would be the meaning of this?:
>
> to_ascii(bytea, integer)
>

it's symmetric. Nothing more.

>
> cheers
>
> andrew
>
>