From Dave@occl-cam.demon.co.uk Wed Jan 29 00:10:16 1997 Received: from relay-7.mail.demon.net (relay-7.mail.demon.net [194.217.242.9]) by dkuug.dk (8.6.12/8.6.12) with SMTP id AAA02899 for ; Wed, 29 Jan 1997 00:10:14 +0100 Received: from occl-cam.demon.co.uk ([158.152.56.116]) by relay-5.mail.demon.net id aa517215; 28 Jan 97 20:52 GMT Received: by occl-cam.demon.co.uk (IBM OS/2 SENDMAIL VERSION 1.3.9)/(3.0sos) id AA0761; Tue, 28 Jan 97 18:02:12 GMT Message-Id: <9701281802.AA0761@occl-cam.demon.co.uk> In-Reply-To: <199701272135.WAA23043@dkuug.dk> Date: Tue, 28 Jan 97 17:55:31 GMT From: Dave Lloyd To: maine@altair.dfrc.nasa.gov Cc: sc22wg5@dkuug.dk Subject: (SC22WG5.1271) Informal Review of Source Processing Draft Standard Richard Maine writes: > 2. I have long considered the #ifdef construct and its relatives > to be a horribly designed feature in that it is extremely > error prone. It is inherently vulnerable to typos. If you > mistype the name, either in the #define or the #ifdef, then > you just get the wrong result - no error message. Even getting > the case of a letter wrong will mess you up, or mistyping > O for 0. I've made such mistakes with cpp more than once myself, > and I've helped other people debug when they made it. I am opposed > to copying this misfeature. I much prefer to see something like in > the Fortran language (or for that matter the C language), where you > test the value of variables instead of testing whether the variable > is defined or not. Agree most strongly! Another good reason to avoid an extra layer of macro expansion on top of normal Fortran is that it makes writing source-form tools a complete pig as you can see completely different syntax depending on the #define settings (often supplied by the compiler). For example the C tool makef which automatically builds headers from the exports is easily confused by macros that expand out to a procedure definition head - such as in use in gcc. Macro-expansion or other source-generation tools should come *before* Fortran source. Regards, ---------------------------------------------------------------------- Dave Lloyd mailto:Dave@occl-cam.demon.co.uk Oxford and Cambridge Compilers Ltd http://www.occl-cam.demon.co.uk/ Cambridge, England http://www.chaos.org.uk/~dave/