From: Paul Mensonides (pmenso57_at_[hidden])
Date: 2003-05-01 15:25:49
Rene Rivera wrote:
>> The whole point, IMO, is to avoid the need for the intrusive syntax
>> in as many places as possible--both in the implementation and in the
>> interface. __comma__, __lparen__, and __rparen__ are the only useful
> I just don't see how you can avoid any "intrusive" syntax. You just
> can't write a language (PP in this case) that "does what you mean,
> not what you say"... grammar gets in the way ;-)
You can't avoid it entirely. As you say, the grammar... However, you can limit
the intrusiveness to only those three tokens and only when they are used.
>> --unless you mean to say that
>> #escape "..." can include arbitrary macros expansions etc. that are
>> delayed until the last possible moment?
> No totally sure what arbitrary macros you mean. But yes, the "escaped"
> token-string can be anything and it would only get inserted/evaluated
> as the _last_ step. So it would have to unwind the parse recursion,
> and then insert the escaped token-string. And with the #eval you
> could control when any currectly accumulated #escape token-strings
> are inserted.
What I meant was something like:
#define ID(x) x
#define MACRO() 123
ID( #escape "MACRO()" )
Are you suggesting that the result should be "MACRO()" or that the
invocation/processing of the escaped string should be deferred until after
top-level scanning moves past it (conceptually)? In that case, it would expand
to "123". BTW, I like the second one better, but only because I can think of,
as usual, pathological usages of it. ;)
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