🚀 go-pugleaf

Apologies if you see this twice.  I don't think this escaped from Digital
before, and I can no longer abuse Berkeley's daemon to get things posted.

In article <1992Oct30.103610.24927@olymp.informatik.uni-bonn.de> hermann@uran.informatik.uni-bonn.de (Hermann Stamm) writes:
>  Define a macro which expands to a function-call
>  with one open bracket but without the closing one.
>  This "allows" a variable number of arguments;

A variable number of C expressions as arguments to the C function, not a
variable number of macro arguments.  A devious user would be able to insert
other stuff as well, though of course that only affects herself and the
poor readers who will have to maintain her program later.

>  the only disadvantage is, that you have to write one
>  more closing than opening bracket in the program.

You could define a second macro to generate the closing parenthesis.

>  - Is this portable/ANSI-conform ?

If done properly, yes.  Each parenthesis (and each bracket and each brace)
stands alone as a token, not like the apostrophese and quotation marks that
delimit character and string constants.

>  - Are there any reasons for not doing it this way (style, ...) ?

Followups to this question should be directed to alt.religion.computers.

>  - What is the better method if more than one argument is the same for
>    all function-calls (the X and L in the below example), the one
>    used for CONTRACT or the one used for EXPAND ?

If you're sure it will always be the same, then just hard-code it in the
macro expansions, instead of making it a macro argument.

>The main reason for not using the variable number of arguments operator
>,... of functions is the loosing of type-checking in the variable
>positions; here type-checking is done at each position!

Huh?  Macro arguments are never type-checked.

>contract(circle C, int l)            ==> contract circle C's 
>					 radius by length l.
>
>contact(rectangle R, int lx, int ly) ==> contract rectangle R's
>					 width by lx and its 
>					 height by ly.

Huh?  I thought we were talking about C.  If you want a C++ answer, go
ask in that group.
--
Norman Diamond       diamond@jit081.enet.dec.com
If this were the company's opinion, I wouldn't be allowed to post it.
"It's been a lovely recession."