openerp-expert-framework team mailing list archive

[Sharoon Thomas <sharoonthomas@xxxxxxxxxxxx>]

Raphael,

But i have a concern, I remember Guido saying something related to this in
the python 3000 change meeting.... I am still searching for the info...

If this is going to be removed in a future version we need to find a
workaround right away....

Cheers!

Sharoon

2009/12/8 Raphaël Valyi <rvalyi@xxxxxxxxx>

> Hey Sharoon,
>
> shame on me, you are absolutely right, I did the test in a Python console
> with "and" instead of "or", that's why I believed "" was casted as True by
> mistake.
> Usually I'm disappointed by Python expression casting vs Ruby. Example of
> this are: table[out_fo_range_index] is casted to Nil (None) in Ruby which is
> more handy than a fucking exception.
> But I should admit that here Python got it right too with "" so it does
> just what you mean and your proposal seems good on all points so far.
>
> Raphaël Valyi
> http://www.akretion.com
>
> 2009/12/8 Sharoon Thomas <sharoonthomas@xxxxxxxxxxxx>
>
> Hi Raphael,
>>
>> It wouldnt break the existing behavioour because by default it should
>> continue to return False.
>>
>> My point was we should be able to specify in the context what should be
>> the null value. If theres no null value specified, then work like how it
>> works now. (Return False)
>>
>> Also the said problem (about  [[ product.price_extra or "No extra cost!"
>> ]]) doesnt exist because "" is treated as False by python.
>> Example:
>>
>> >>> price_extra = ""
>> >>> print (price_extra or "No extra cost")
>> No extra cost
>>
>> For python {},[],"",'' are all False type in logical operations
>>
>>
>>
>> 2009/12/8 Raphaël Valyi <rvalyi@xxxxxxxxx>
>>
>>
>>>> The generic issue IMHO is the open erp browse object/class which has two
>>>> problems:
>>>>
>>>>    1. raises an error when the expression is wrong eg.
>>>>    user.partner_id.name (if partner id doesnt exist or is false it
>>>>    returns err so we are forced to write user.partner_id and
>>>>    user.partner_id.name)
>>>>    2. if a field is empty it return False, it should be possible to
>>>>    selectively change what should be the return value if database/computed
>>>>    value is null. So if we can selectively opt to choose like
>>>>    self.pool.get('model').browse(cr,uid,ids,context={'null_value' = ''}) and if
>>>>    browse object respects this, there should be no problem.
>>>>
>>>> Sharoon, nice suggestion, and I agree for 1). However, for 2), returning
>>> "" instead of False would break a lot commonly used boolean expressions.
>>> For instance [[ product.price_extra or "No extra cost!" ]] would return
>>> "" rather than "No extra cost!" if we do what you propose. So I don't think
>>> this would be more user friendly than the current awkwardness.
>>> What I propose for 2) is a bit different. I propose that the expression
>>> evaluator, change False to "" but only at the expression level (once the
>>> whole [[ ]] block has been evaluated), not at the object attribute level
>>> which would screw up boolean expressions.
>>>
>>> Do you agree on this? Do you see any way of doing it?
>>>
>>> Raphaël Valyi
>>> http://www.akretion.com
>>>
>>
>>
>>
>> --
>> Sharoon Thomas
>> Business Analyst & ERP Consultant
>> http://bit.ly/5FAJKU
>>
>
>


-- 
Sharoon Thomas
Business Analyst & ERP Consultant
http://bit.ly/5FAJKU