[Dev-luatex] return value of filter callbacks

Manuel Pégourié-Gonnard mpg at elzevir.fr
Fri Nov 5 14:56:13 CET 2010


Le 05/11/2010 14:52, Taco Hoekwater a écrit :
> On 11/05/2010 02:46 PM, Manuel Pégourié-Gonnard wrote:
>> Le 05/11/2010 14:22, Taco Hoekwater a écrit :
>>> In all these cases the result of returning a boolean is the same:
>>>
>>>     false == callback has failed
>>>     true == callback has run ok, but nothing has been changed
>>>
>>> the latter case (true) is interesting because it allows a speed
>>> optimization that can be considerable. I could have sworn this was
>>> mentioned in the manual, but I cannot find it myself either.
>>
>> Ok, thanks for the clarification. Just to be sure: in case the function returns
>> false, and error will be issued, right?
> 
> Eh ... no. You have to raise an error yourself, if you want that.
> 
Hum, so what is the purpose of returning false rather than true, if no action is
taken based on this value?


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