[Zope3-dev] Re: Existential question about BytesWidget v.s. ASCIIWidget

[Stéphane Brunet]

Jim Fulton wrote:

>
> First, you are confusing schema definitions and widgets.  You should
> start from the definitions of the field types.
>
That was a typo... Sorry for the confusion :-P

> As Derrick (sort of) suggested, Bytes fields are fields that contain
> Python strings, as opposed to Text fields, which contain unicodes.
> Bytes values can contain pretty much arbitrary string values.  For
> example, a Bytes fields could contain image data.
>
> ASCII fields contain only 7-bit ascii data. ASCII fields were introduced
> in recognition that many Bytes fields were being used in cases of source
> code where the desire was, mainly, to avoid unicode.
>
I see! I have just found the definition of ASCII fields which are 
derivatives of Bytes field but with a validate function (for the 0-127 
range).
Even if ASCII can be stored in Bytes field, the choice has been made to 
separate the two types of fields in order to add this validation 
function. Right ?

> There are lots of schemas that are using Bytes that should probably
> use ASCII or Text instead.  I would say that most or all occurrences
> of BytesLine should use ASCIILine instead. Unfortunately there is no
> ASCIILine. Sigh.
>
> The widgets are probably out of sync with these definitions.
> I suspect that the Bytes widgets behave the way they do because
> they were developed before we had an ASCCII type.

If I try to sum up a little bit what I understand :
 * concerning fields :
    - Bytes field should be used for raw binary data or byte-friendly 
text encoding (e.g. UTF-8) _except ASCII_.
    - BytesLine field should be used for byte-friendly single-line text 
encoding (e.g. UTF-8) _except ASCII_.
    - ASCII field should be used for multi-line ASCII text.
    - ASCIILine field for single-line ASCII text( e.g. MIME content type 
field in the "File" package), which must be added in zope.schema
 * concerning widgets :
    - ASCIIWidget should be preferred to BytesWidget because its name 
clearly informs about the expected text encoding (although 
Bytes(Area)Widget accepts only ASCII text).
    - ASCIIAreaWidget should be added in order to replace 
BytesAreaWidget for multiline ASCII fields.
    - The need for Bytes(Area)Widgets is just unclear in my mind...

>
> It woul dbe great for someone to try to get this cleaned up. :)
>
I would be ready to put some work on it as soon as everything is clear 
in my mind about the use of Bytes v.s. ASCII fields and 
Bytes(Area)Widgets. Moreover, this is related to the issue 302 which I 
am trying to solve (the job is almost done concerning the encoding 
problems).

Stéphane