On Thu, 2008-04-03 at 06:30 +1000, Michael D. Setzer II wrote: > > On 2 Apr 2008 at 18:09, Matthew Saltzman wrote: > > On Wed, 2008-04-02 at 09:48 -0700, Les wrote: > > > On my punch cards they did. Every card had a number sequential to the > > > sequence. The punch we used inserted them automatically. Well, the > > > programming card did. The reference number used for calls may have been > > > different, but I don't remember it. > > > > Those weren't line numbers per se (in the sense that BASIC had line > > numbers, for example). In FORTRAN, an 80-column card was divided into > > fields: > > > > Column 1: 'C' indicated a comment line, ' ' a code line. > > > > Columnt 1-5: is for line numbers and on many compilers they had to be right > aligned. OK, but these are the statement labels described below, not line numbers per se. > > > Column 2-6: Statement label numbers. These were arbitrary numbers used > > as targets for FORMAT, GOTO and "computed GOTO" (now *that* was a flow > > control concept!), and DO statements. These did not have to obey any > > ordering rules. There was no concept of an if-else block or a while > > loop with a logical test, so flow control was handled by GOTOs of some > > variety. Targeted statements were usually CONTINUE statements (no-ops), > > because there was some ambiguity regarding when the targeted statement > > was actually executed, and because it made reorganizing the flow a bit > > easier (especially with punchcards[1]). > > > > Column 6: Was used for continuing information from the previous card. > Generally putting a 1 in column 6 for the first continuation line, and 2, and so > on, but most didn't care. COBOL uses Column 7 for this, and uses a hyphen > if splitting a word or quoted text. Damn, forgot the continuation character. > > > > Column 7-72: Code. > > > > Column 73-80: Ignored. Intended to be used for sequence numbers so you > > could sort the cards down in order if somebody dropped the deck. The > > numbers could be anything really, for example a three-letter alpha code > > identifying the deck and a four-digit sequence number. > > > > (Somebody is bound to correct me on the actual column numbers, now...) Thanks for the corrections. I wasn't near my FORTRAN Coloring Book (Roger Kaufman, Cambridge, Massachusetts and London England, The MIT Press, 1978. 285 pp., paperback ISBN 0 262 61026 4, http://www.seas.gwu.edu/~kaufman1/FortranColoringBook/ColoringBkCover.html) when I wrote that. -- Matthew Saltzman Clemson University Math Sciences mjs AT clemson DOT edu http://www.math.clemson.edu/~mjs
