Re: How to support a non-standard encoding?

[Thomas Rachel]

Am 06.01.2012 21:00 schrieb jmfauth:


Another simple approach, os independent.

You probably do not write your code in iso-6937, but
you only need to encode/decode some bytes sequence
"on the fly". In that case, work with bytes, create
a couple of coding / decoding functions with a
created  [*] as helper. It's not so complicate.
Use  Py2 or  Py3 (the recommended
way ;-) ) as pivot encoding.


These coding/decoding functions are exactly the way to create a codec. 
I. e., it is not much more.



Thomas
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Re: How to support a non-standard encoding?

[Ivan]

Dear jmf, Tim

Thanks for these pointers.  They look v useful.

I'll have a go and report back (with success I hope).

Best wishes

Ivan

On 06/01/2012 20:42, Tim Wintle wrote:

On Fri, 2012-01-06 at 12:00 -0800, jmfauth wrote:

The distibution of such a codec may be a problem.


There is a register_codec method (or similar) in the codecs module.

Tim





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Re: How to support a non-standard encoding?

[Tim Wintle]

On Fri, 2012-01-06 at 12:00 -0800, jmfauth wrote:
> The distibution of such a codec may be a problem.

There is a register_codec method (or similar) in the codecs module.

Tim


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Re: How to support a non-standard encoding?

[jmfauth]

On 6 jan, 11:03, Ivan  wrote:
> Dear All
>
> I'm developing a python application for which I need to support a
> non-standard character encoding (specifically ISO 6937/2-1983, Addendum
> 1-1989).  Here are some of the properties of the encoding and its use in
> the application:
>
>    - I need to read and write data to/from files.  The file format
>      includes two sections in different character encodings (so I
>      shan't be able to use codecs.open()).
>
>    - iso-6937 sections include non-printing control characters
>
>    - iso-6937 is a variable width encoding, e.g. "A" = [41],
>      "Ä" = [0xC8, 0x41]; all non-spacing diacritical marks are in the
>      range 0xC0-0xCF.
>
> By any chance is there anyone out there working on iso-6937?
>
> Otherwise, I think I need to write a new codec to support reading and
> writing this data.  Does anyone know of any tutorials or blog posts on
> implementing a codec for a non-standard characeter encoding?  Would
> anyone be interested in reading one?
>


Take a look at the files, Python modules, in the
...\Lib\encodings. This is the place where all codecs
are centralized. Python is magically using these
a long there are present in that dir.

I remember, long time ago, for the fun, I created such
a codec quite easily. I picked up one of the file as
template and I modified its "table". It was a
byte <-> byte table.

For multibytes coding scheme, it may be a litte bit more
complicated; you may take a look, eg, at the mbcs.py codec.

The distibution of such a codec may be a problem.



Another simple approach, os independent.

You probably do not write your code in iso-6937, but
you only need to encode/decode some bytes sequence
"on the fly". In that case, work with bytes, create
a couple of coding / decoding functions with a
created  [*] as helper. It's not so complicate.
Use  Py2 or  Py3 (the recommended
way ;-) ) as pivot encoding.

[*] I also created once a such a dict from
# 
http://www.unicode.org/Public/MAPPINGS/VENDORS/MICSFT/WindowsBestFit/bestfit1252.txt

I never checked if it does correpond to the "official" cp1252
codec.

jmf
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Re: How to support a non-standard encoding?

[Ivan Uemlianin]

Dear Tim

Thanks for your help.

> If your system version of iconv contains that encoding, ...

Alas, it doesn't:

$ iconv -l |grep 6937
$

Also, I'd like to package the app so other people could use it, so I 
wouldn't want to depend too much on the local OS.


Best wishes

Ivan


On 06/01/2012 13:47, Tim Wintle wrote:

On Fri, 2012-01-06 at 10:03 +, Ivan wrote:

Dear All

I'm developing a python application for which I need to support a
non-standard character encoding (specifically ISO 6937/2-1983, Addendum
1-1989).


If your system version of iconv contains that encoding (mine does) then
you could use a wrapped iconv library to avoid re-inventing the wheel.

I've got a forked version of the "iconv" package from pypi available
here:



.. it should work on python2.5-2.7

Tim




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Ivan A. Uemlianin
Llaisdy
Speech Technology Research and Development

i...@llaisdy.com
 www.llaisdy.com
 llaisdy.wordpress.com
  github.com/llaisdy
 www.linkedin.com/in/ivanuemlianin

"Froh, froh! Wie seine Sonnen, seine Sonnen fliegen"
 (Schiller, Beethoven)

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Re: How to support a non-standard encoding?

[Tim Wintle]

On Fri, 2012-01-06 at 10:03 +, Ivan wrote:
> Dear All
> 
> I'm developing a python application for which I need to support a 
> non-standard character encoding (specifically ISO 6937/2-1983, Addendum 
> 1-1989).

If your system version of iconv contains that encoding (mine does) then
you could use a wrapped iconv library to avoid re-inventing the wheel.

I've got a forked version of the "iconv" package from pypi available
here:



.. it should work on python2.5-2.7

Tim

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How to support a non-standard encoding?

[Ivan]

Dear All

I'm developing a python application for which I need to support a 
non-standard character encoding (specifically ISO 6937/2-1983, Addendum 
1-1989).  Here are some of the properties of the encoding and its use in 
the application:


  - I need to read and write data to/from files.  The file format
includes two sections in different character encodings (so I
shan't be able to use codecs.open()).

  - iso-6937 sections include non-printing control characters

  - iso-6937 is a variable width encoding, e.g. "A" = [41],
"Ä" = [0xC8, 0x41]; all non-spacing diacritical marks are in the
range 0xC0-0xCF.

By any chance is there anyone out there working on iso-6937?

Otherwise, I think I need to write a new codec to support reading and 
writing this data.  Does anyone know of any tutorials or blog posts on 
implementing a codec for a non-standard characeter encoding?  Would 
anyone be interested in reading one?


With thanks and best wishes

Ivan


--

Ivan A. Uemlianin
Llaisdy
Speech Technology Research and Development

i...@llaisdy.com
 www.llaisdy.com
 llaisdy.wordpress.com
  github.com/llaisdy
 www.linkedin.com/in/ivanuemlianin

"Froh, froh! Wie seine Sonnen, seine Sonnen fliegen"
 (Schiller, Beethoven)

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