Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!cs.utexas.edu!uunet!ncrlnk!ncr-sd!rb-dc1!shapiro From: shapiro@rb-dc1.UUCP (Mike Shapiro) Newsgroups: comp.lang.fortran Subject: Re: dpANS Fortran 8x Message-ID: <561@rb-dc1.UUCP> Date: 13 Jun 89 17:17:35 GMT References: <2721@elxsi.UUCP> Reply-To: shapiro@rb-dc1.SanDiego.gould.UUCP (Michael Shapiro) Distribution: usa Organization: Encore Computer, San Diego (was Gould/GSD, soon to be extinct) Lines: 41 In article bill@ssd.harris.com (Bill Leonard) writes, regarding horizontal tabs in Fortran source: >Well, one reason is that we can't get a majority to agree on what a tab >would mean. Those who want tabs usually want it to mean "however many >spaces it produces on my terminal when I display the file" -- try getting >that into a standard! The problem really lies in the fact that, while tab >is a "standard" character, it has an implementation-defined meaning. In >fact, on some systems the user can change the tab settings, thus changing >the "meaning" of tab dynamically! If all X3J3 did were to allow tabs in >source files, but didn't specify it's meaning, portability would not >improve one iota. One possible partial solution, which can be considered implementation-independent, is that used in Gould Common Fortran: A tab character in any of the first six positions of a line is interpreted as a skip to position 7. This indi- cates that all the following characters in the line are to be treated as a statement. A tab character anywhere else in the line is treated as a space. This rule seems to apply to the statement form, indicating a statement must be from columns 7 through 72. It doesn't say whether a tab character can be part of a character constant and, if so, what it means. The new dpANS Fortran allows the fixed format as an option and a new free format, eliminating the column restrictions. The new standard allows tab characters (as additional characters representable on the processor) in "character constants, character string edit descriptors, comments, and input/output records." I have the feeling that many implementors will allow tabs elsewhere in free form source, treating them as spaces for the 132 characters in a line limit. -- Michael Shapiro, Encore Computer Corporation (formerly Gould/GSD) 15378 Avenue of Science, San Diego, CA 92128 (619)485-0910 UUCP: shapiro@rb-dc1 (This location will close, starting July 10. I will be moving on.)