StringIO objects sharing a buffer

[Thomas Lotze]

Hi,

I want to implement a tokenizer for some syntax. So I thought I'd subclass
StringIO and make my new class return tokens on next().

However, if I want to read tokens from two places in the string in turns,
I'd either need to do some housekeeping of file pointers outside the
tokenizer class (which is ugly) or use two tokenizers on the same data
buffer (which seems impossible to me using my preferred approach as a
file-like object has exactly one file pointer).

Is there a way for multiple StringIO objects to share a buffer of data, or
do I have to give up on subclassing StringIO for this purpose? (An
alternative would be a tokenizer class that has a StringIO instead of
being one and do the file pointer housekeeping in there.)

--
Thomas

[Mathias Waack]

Re: StringIO objects sharing a buffer

Thomas Lotze wrote:
[color=blue]
> Is there a way for multiple StringIO objects to share a buffer of
> data, or do I have to give up on subclassing StringIO for this
> purpose? (An alternative would be a tokenizer class that has a
> StringIO instead of being one and do the file pointer housekeeping
> in there.)[/color]

I'm not sure if I understand the problem right, but there is a rule
of thumb:
Prefer delegation to inheritance. If you can use delegation, avoid
inheritance. Esp. on python, where (from the point of view of usage)
there is no distinction between delegation or inheritance.

Mathias