In similar manner to the similar question about generics. What was its first appearance, and how did spread to C?
edit: corrected question based on Jon Skeet's answer (; is a terminator, not a separator)
+2
A:
It's not a separator in C - it's a terminator.
However, I believe ALGOL may have been the first to use the semicolon in this sort of way.
Jon Skeet
2009-08-20 20:22:53
separator as in "statements separator" ?
chakrit
2009-08-20 20:28:29
thanks, I corrected the question
bandi
2009-08-20 20:31:21
Careful. I think in Algol the ; have been a separator (as it is in Pascal). Not a terminator (as it is in C and Ada).
S.Lott
2009-08-20 20:32:13
As a totally unrelated aside, OCaml's ";" is really an operator, not a terminator. It has the type unit -> 'a -> 'a, where the operator accepts two inputs and returns the second. There's a little blurb on this page (http://www.ocaml-tutorial.org/the_structure_of_ocaml_programs) which describes the ";" operator in detail.
Juliet
2009-08-20 20:34:13
http://www.csci.csusb.edu/dick/samples/algol60.syntax.html#separator
S.Lott
2009-08-20 20:34:47
@S.Lott: Made the answer more ambiguous :)
Jon Skeet
2009-08-20 20:55:46
its called a terminator in C, but it acts like a separator
RBarryYoung
2009-08-20 21:07:20
@RBarryYoung: No, it's a statement terminator in C. The way to tell is to look at the last statement in a block: does it need a ; or not? If so, it's a terminator, otherwise it's a separator. Terminators are generally easier on the programmer than separators.
David Thornley
2009-08-20 21:58:34
No, the way to tell a terminator is: s it required to terminate every statment, as it was in COBOL an Jovial? It does not work that way in C. The most that can be sais in C is that ";" is more or a terminator there, than it was in Algol, Simula or Pascal. But it's still not a true terminator.
RBarryYoung
2009-08-20 22:09:29
And actually, most from that time and up through the mid to late 80's felt that C's inconsistent terminator/separator aproach was hardest of all on programmers. (after that everyone coming out of college had been "baby ducklinged" on C and nolonger seemed capable of objective thought on the matter). C's approach to semicolons and statement termination is really onlu an advantage for the parser/complier writers and is in fact merely a burden for the programmer. Especially since it is entirely possbile to have languages with NO statement terminators needed.
RBarryYoung
2009-08-21 13:40:04
**@R Barry Young:** 'k, the history lesson is great, but would have been a lot more relevant if you'd taken time to explain why you consider it to act as a separator first.
Shog9
2009-08-21 18:34:02
A:
Pascal had semicolons as terminators before C did; not sure if it was the first language to have them, though.
fbrereto
2009-08-20 20:24:23
pascal as them as separators - terminators are similar but they are different.
plinth
2009-08-20 21:05:49
+1
A:
Definitely ALGOL.
Hmm, somebody changed the question. That's not quite cricket.
As for how it spread, well semicolons spread Algol 60 -> Simula -> C. K+R said that Pascal didnt influence them, IIRC, though some disputed this clam.
Statement terminators (other than new-line) spread from COBOL -> Jovial -> C. Though each had a different character as the teminator.
RBarryYoung
2009-08-20 21:05:01
FORTRAN used column 72 of a punch card as a terminator, unless there was a continuation character in column 6 of the next card. (Don't ask how I know.) Lisp, the other survivor of the really early languages, just had statements delimited by parentheses.
David Thornley
2009-08-20 22:02:24
No, you mean that F77 used a *continuation* character in column72. There was no termination character in F77 (unless you count new-lines which they didnt then).
RBarryYoung
2009-08-20 22:04:54
I dimly remember the amazing new concept that the thing between lines of code could be considered a character, even though, in ASCII, that's exactly what it was.
Mike Dunlavey
2009-08-24 14:03:21
A:
ALGOL is my guess too.
The significance is that it freed the user from punch-card-style fixed format.
If you have to use Fortran 77, you know what that means.
Mike Dunlavey
2009-08-20 21:42:58
And, IIRC, it was valid in FORTRAN-77 to use it in non-Zoned format.
RBarryYoung
2009-08-20 21:48:08
@RBarry: don't you still have the line-length restriction and continuation characters? We hit that all the time.
Mike Dunlavey
2009-08-21 00:30:27
Mike Dunlavey: 1 statement per line, yes. The rest, I am not sure, it's hard to sort out all of the different versions and the propietary enhancements from the standard features. (it *was* 25-35 years ago :- ).
RBarryYoung
2009-08-23 17:10:21
IMHO, the more likely reason that Algol pioneered the non-line-break style of statement separation/termination ha to do with it's most common storage, presentation and execution medium: Academic Journals. Being able to reformat the line-breaks would have been a real boon for the type-setters. (COBOL and FORTRAN's default medium on the other-hand was punched-cards, which explains why they would favor not only line-break sensitivity, but vel "zone" (column number) sensitivity.
RBarryYoung
2009-08-23 17:16:46
@RBarry: That's an interesting insight. I also wonder if it had to do with the use of paper tape by DEC. I can't remember what the Burroughs machines used for media, but I don't think it was punch cards.
Mike Dunlavey
2009-08-24 12:11:27
... I also just wiki'd Burroughs, then ALGOL-58, then Backus-Naur-Form, then Compound (begin-end) Statements. I didn't find a specific reference to semicolons, but it had to be in there.
Mike Dunlavey
2009-08-24 13:56:13
I actually worked for DEC for 10 years, but they were late to most of this (DEC was a player c.73 to 90, most of this, except F77 was done prior to 72). DEC's paper-tape as descendend from the teletype ASR/KSR-33 paper-tape readers (attached to the teletypes, IIRC). But paper-tape was never a primary medium for any langage, it was always a backup, archival or distribution medium, not the preferred one for developers or execution. I geuss it was really an early substitute for MagTape in many ways.
RBarryYoung
2009-08-24 17:11:18
I don't think that Algol-58 had semicolons. Before my time actually, but everything I've read implies it was introduced in Algol-60.
RBarryYoung
2009-08-24 17:12:35
Mike Dunlavey
2009-08-25 00:06:20