Re: magic variables for included fragments

[Ralf Wildenhues]

Hi Akim,

* Akim Demaille wrote on Wed, Dec 10, 2008 at 10:21:50AM CET:
> Le 4 déc. 08 à 09:38, Ralf Wildenhues a écrit :
>
>>> I have a silly question, but...  is it really known for a fact that  
>>> some Make out there do not support "include if it exists"?
>>
>> This question is not relevant to the problem.

Erm.  Thank you for noticing that I misunderstood your question,
and replied nonsense here ...

>> Automake requires some
>> 'make'-provided inclusion mechanism to work, otherwise dependency
>> tracking will not work.  What is the question is: do we need to use an
>> inclusion mechanism that fails if the file to be included does not  
>> exist yet?  In general, the answer is "yes", because there are make
>> implementations that provide no other.

... but tried to address the actual issue here.

> Ok.  And these makes can be fooled to implement the feature by computing 
> the file name at make-time instead of passing a litteral?

Not quite sure I follow here yet.  Yes, I think it is possible to use
macro names in @am__include@ statements (we already use $(DEPDIR)).  But
what would it buy us?  'make' typically requires all unconditionally
included files to be present, before it thinks of taking any further
action.

Thanks for enlightening me.

>> And even with those that do,
>> like GNU make, one would not want to hide problems where the included
>> snippets have buggily not been included as needed.
>
> You have a point, but at some point, it becomes more a burden than a  
> feature :(  I am regularly bitten by the schizophrenic implementation of 
> this feature, static parts at config.status time, and the rest at  
> runtime.

Fully agreed.

Cheers,
Ralf