[Lightning] Re: Lightning source compatibility

[Ludovic Courtès]

Hi,

Paulo César Pereira de Andrade
<address@hidden>
writes:

>>>   Another good advantage (other than strict type/value checking) is
>>> compile time. The pseudo assembler I use as a testing tool, at
>>>
>>>
>>> http://code.google.com/p/exl/source/browse/trunk/check/lightning/lightning.c
>>>
>>> compiles roughly 5 times faster now, the significant speed increase I
>>> suppose is because it does not need to parse a large sequence of
>>> nested macro calls, and then a large amount of duplicated expressions.
>
>   I was actually expecting it to become slower, but it seems the C 
> preprocessor
> is the problem, so, better not to abuse macros :-)

OTOH, how does this affect compilation time of a smaller file (the one
above contains 4000+ lines, with many large macros expansions)?  More
importantly, does compilation time really matter?

And if cpp is slow on some pathological input, then cpp hackers could
analyze whether it makes sense to optimize it, as opposed to having cpp
users change their coding style just to work around the slowness.  :-)

Thanks,
Ludo’.