Re: client side syntax error localisation for psql (v1)

> Please find attached my first attempt at providing a localisation
> information on the client side for syntax errors in "psql". Basically, one
> function is added which takes care of the burden. I put a lot of
> comments in the function to try make it clear what is going on.
> 
> It validates for me against current cvs head.
> 
> I've also added new regression tests in "errors.sql".
> 
> Although I have taken great and painful care to deal with multi-byte
> encodings, I'm not sure how I can validate that, as I don't have some
> japanese terminal to play with.

As far as I understand your code, it will be broken on many multi byte
encodings.

1) a character is not always represented on a terminal propotional to  the storage size. For example a kanji character in UTF-8 encoding  has a storage size of 3 bytes while it occupies spaces only twice  of ASCII characters on a terminal. Same thing can be said to LATIN  2,3 etc. in UTF-8 perhaps.

2) It assume all encodings are "ASCII compatible". Apparently some  client-side-only encodings do not satisfy this request. Examples  include SJIS, Big5.

I think 2) would be solved by carefull codings. 

However 1) is hard to solve. We need kind of a mapping table between
"storage size" and "terminal size" for each encoding. Note that this
is not new problem, and sophiscated editors such as Emacs (mule) has
already concur that.
--
Tatsuo Ishii