[m-dev.] context "macros"

[Julien Fischer]

On Thu, 27 Mar 2008, Ian MacLarty wrote:

> On Wed, Mar 26, 2008 at 11:18:47AM +1100, Julien Fischer wrote:
>>
>> On Wed, 26 Mar 2008, Ralph Becket wrote:
>>
>>> Julien Fischer, Tuesday, 25 March 2008:
>>>>
>>>> On Tue, 25 Mar 2008, Peter Wang wrote:
>>>>
>>>>> What do you think of adding support for __file__, __pred__, __line__
>>>>> "macros"?  These would expand into strings or integers like the
>>>>> corresponding C macros.
>>>>
>>>> I have often though something like this would be useful, particularly
>>>> given that the this_file/0 functions we use in the compiler don't
>>>> extend well when sub-modules are involved (you have to qualify them
>>>> if the parent also defines a this_file/0 function.)
>>>>
>>>>> My concern was just about the syntax.  __foo__ has the advantages of
>>>>> following C and requiring no changes to the parser.
>>>>
>>>>> __line__ is a
>>>>> little bit sticky for referential transparency, but __file__ and
>>>>> __pred__ would just act like variables assigned at the start of the
>>>>> predicate.
>>>>
>>>> An alternative syntax suggestion: @line@, @file@ etc ...
>>>
>>> We haven't used the # symbol yet, as I recall.
>>
>> Yes we do, it is used with #line directives (ref. man 2.2).
>>
>> (On an slightly related matter I think we should replace pragma
>> source_file with #file.)
>>
>
> It would be nice if we supported directives like:
>
> #line 5 "source.m"
>
> since then m4's --synclines option would work.

Out of curiosity, why do you want it to work?

Julien.
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