defining a comment?

[will summers]

In article <678 at ksuvax1.cis.ksu.edu> vopata at ksuvax1.cis.ksu.edu (Ed Vopata)
writes:
 > In article <855 at vsi.UUCP> friedl at vsi.UUCP (Stephen J. Friedl) writes:
 
 > The following in a sample program which will demonstrate the use of
 > STARTCOM and ENDCOM macros for defining the beginning and ending of a C
 > Comment. ...  I have
 > compiled this program on a couple of C compilers (one provided with 4.3 BSD
 > and one provided by AT&T) and the program works.
 >
 > Please note that in the "#define STAR *" there must be only 1 space between
 > the "STAR" and the "*" otherwise STARTCOM  may look like "/   *".
 >
 > ------- cut here -------
 > #define STAR *
 > #define STARTCOM /STAR
 > #define ENDCOM STAR/
 >
 > STARTCOM
 >   Comment.c  -- by Edward Vopata (9/22/88)
 >
 >   Put the text of the comment here.
 >   Multiple lines are allowed.
 > ENDCOM
 
Interesting... Will it always work under dpANS?  (I doubt it).  Even
though the code will look like
 
/*
  < comments >
*/
 
after translation phase 4, subsequent translation phases need not interpret
this as a comment: they expect comments to have been stripped. (2.1.1.2)
 
On second thought "need not" may not be strong enough:  perhaps it should
be "subsequent translation phases **may not** interpret
this as a comment".  Since STARTCOM..ENDCOM will generate code with
syntax errors, a conforming implementation -must- issue a diagnostic
message. (2.1.1.3)
 
As long as a "preprocess only" option is available, however,
running the code through -twice- would seem to work under dpANS...  But
then a simpler pre-compile pass can map STARTCOM to /* if desired.
 
dpANS aside, STARTCOM..ENDCOM seems non-portable unless the order of
macro-expansion/comment-striping is specified somewhere pre-ANSI.  It does
not seem to have been specified in K&Rv1.
 
    \/\/ill
 


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