From: dobrien@seas.gwu.edu (David O'Brien)
Subject: Re: "Subtract C, add Ada"
Date: 14 Jan 1995 00:24:13 GMT
Date: 1995-01-14T00:24:13+00:00 [thread overview]
Message-ID: <3f75jd$2tf@cronkite.seas.gwu.edu> (raw)
In-Reply-To: 3f5s92$3id@info.epfl.ch
Laurent Gasser (gasser@masg1.epfl.ch) wrote:
: In article <3f4mbe$rud@cronkite.seas.gwu.edu>, dobrien@seas.gwu.edu (David O'Brien) writes:
: |> R.A.L Williams (bill@valiant) wrote:
: |> : My experience of writing software and running software projects in C
: |> : highlights four common low-level C errors:
: |> : 1. = instead of == and vice versa
: |>
: |> I have to wonder. What if C defined the logical equals operator to be
: |> "=" and the assignment operator to be ":=" just like Ada, Algol, Pascal,
: |> Modula-x, etc? Would this error still exist???
: The problem is in the language definition, not in the choice of symbols.
: C is one of the rare language I use to allow having an assignment after
: the if statement. All other languages only allow for a boolean test.
Yep, that's my point. The argument of character choice really isn't what
is at the essence of the problem. Rather it is the language definition.
: I never saw a good reason for allowing this.
Simply the paradigm of C that *every* statement has a value. And C has
no special logical values. So C has "values are values" akin to Ford's
offering of the Model-T, "any colour you want, as long as it's black".
I'm guessing Ritchie did this for the same reason as Henry Ford - to
simply things. Which gave us the situation we have.
In most languages the grammar would be:
conditional_statement ::= if <logical_expression> then
Which in C becomes:
conditional_statement ::= if ( <expression> ) <statement>
and thus ``<expression>'' must include ``<lvalue> = <expression>''.
-- David O'Brien (dobrien@seas.gwu.edu)
next prev parent reply other threads:[~1995-01-14 0:24 UTC|newest]
Thread overview: 89+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <3etund$hnr@miranda.gmrc.gecm.com>
1995-01-12 9:56 ` "Subtract C, add Ada" Erik Svensson
[not found] ` <3f0n6b$qnp@theopolis.orl.mmc.com>
[not found] ` <3f3cq3$4tu@gnat.cs.nyu.edu>
1995-01-12 14:25 ` uninitialzed variables Richard Kenner
1995-01-12 14:44 ` "Subtract C, add Ada" Norman H. Cohen
1995-01-13 1:51 ` David O'Brien
1995-01-13 12:38 ` Laurent Gasser
1995-01-13 20:53 ` John DiCamillo
[not found] ` <3f8fnf$c8p@gamma.ois.com>
1995-01-16 11:02 ` Matt Kennel
[not found] ` <milodD2IFpG.329@netcom.com>
1995-01-17 21:39 ` R. William Beckwith
[not found] ` <3fa11q$sdh@gnat.cs.nyu.edu>
1995-01-16 20:20 ` David Moore
1995-01-14 0:24 ` David O'Brien [this message]
1995-01-20 4:43 ` Samuel Mize
1995-01-21 20:28 ` David O'Brien
1995-01-22 21:12 ` Robert Dewar
1995-01-23 18:35 ` Norman H. Cohen
1995-01-23 19:18 ` John Cosby - The Coz
1995-01-24 14:11 ` Samuel Mize
[not found] ` <3g655n$q5k@theopolis.orl.mmc.com>
1995-01-30 15:33 ` Ada vs. C Martijn Bak
1995-01-14 10:37 ` "Subtract C, add Ada" Keith Thompson
[not found] ` <3fcjgt$b0v@cronkite.seas.gwu.edu>
1995-01-16 18:47 ` Robert Dewar
[not found] ` <D2It0r.4rp@inmet.camb.inmet.com>
1995-01-17 14:11 ` Norman H. Cohen
[not found] ` <3g9nir$fpl@gnat.cs.nyu.edu>
1995-01-28 20:23 ` Increment operator (+=) Jacob Sparre Andersen
[not found] ` <3gc5be$frj@Starbase.NeoSoft.COM>
1995-01-29 12:51 ` Adding in COBOL Robert Dewar
1995-02-10 13:49 "Subtract C, add Ada" R.A.L Williams
[not found] <3gsr0e$oin@miranda.gmrc.gecm.com>
1995-02-07 16:58 ` Mark S. Hathaway
1995-02-08 7:39 ` Travis C. Porco
1995-02-08 16:07 ` Fred J. McCall
1995-02-08 21:30 ` Garlington KE
-- strict thread matches above, loose matches on Subject: below --
1995-01-31 9:34 R.A.L Williams
1995-02-01 16:45 ` Charles H. Sampson
1995-01-23 8:49 R.A.L Williams
1995-01-25 23:18 ` Charles H. Sampson
1995-01-20 10:20 R.A.L Williams
1995-01-20 13:22 ` Renaud HEBERT
1995-01-24 3:35 ` David Moore
1995-01-25 5:38 ` Robert Dewar
1995-01-28 16:35 ` Jules
1995-01-29 8:06 ` Matt Kennel
1995-01-30 5:31 ` Michael Feldman
1995-01-31 22:22 ` David O'Brien
1995-01-24 20:23 ` N. Mellor
1995-01-25 8:50 ` Robb Nebbe
1995-01-25 14:19 ` John Volan
1995-01-26 5:07 ` Samuel Mize
1995-01-26 18:51 ` Mark A Biggar
1995-01-21 15:18 ` Robert Dewar
1995-01-21 21:03 ` David O'Brien
1995-01-23 3:09 ` Jay Martin
1995-01-23 12:50 ` Andrew McConnell
1995-01-24 0:54 ` Matt Kennel
1995-01-25 17:03 ` Norman H. Cohen
1995-01-26 1:13 ` Dr. Richard Botting
1995-01-26 14:32 ` Anders Juul Munch
1995-01-24 0:17 ` Bob Kitzberger
1995-01-23 20:46 ` Robert Firth
1995-01-24 14:25 ` Samuel Mize
1995-01-25 7:27 ` David O'Brien
1995-01-25 12:14 ` Robert A Duff
1995-01-25 5:57 ` David O'Brien
[not found] ` <3g9rf0$71k@Starbase.NeoSoft.COM>
1995-01-28 21:08 ` David O'Brien
1995-01-31 18:07 ` Samuel Mize
1995-02-01 10:23 ` Samuel Mize
1995-01-30 0:24 ` Mark S. Hathaway
1995-01-31 3:30 ` Jay Martin
1995-02-01 13:25 ` Jesper Kaagaard
1995-01-20 9:33 R.A.L Williams
[not found] <3fgphd$sc3@rational.rational.com>
1995-01-20 5:51 ` RonaldS60
1995-02-07 13:55 ` Robert C. Soong
[not found] <3fdcoi$chn@miranda.gmrc.gecm.com>
1995-01-20 5:01 ` Samuel Mize
1995-01-20 22:07 ` Garlington KE
1995-01-24 5:02 ` R_Tim_Coslet
1994-12-30 16:06 Mitch Gart
1995-01-03 19:04 ` whiting_ms@corning.com (Matt Whiting)
1995-01-05 4:31 ` Michael Feldman
1995-01-04 21:40 ` Fred McCall
1995-01-05 4:30 ` Richard Pattis
1995-01-05 16:07 ` Kevin Weise
1995-01-06 13:06 ` Jahn Rentmeister
1995-01-06 16:47 ` Laurent Gasser
1995-01-06 17:29 ` David Weller
1995-01-06 17:30 ` David Weller
1995-01-10 18:28 ` Bob Kitzberger
1995-01-06 23:36 ` Kenneth Almquist
1995-01-04 22:45 ` Jay M. Martin
1995-01-05 4:37 ` Michael Feldman
1995-01-05 18:08 ` Jay Martin
1995-01-05 23:56 ` Robert Dewar
1995-01-08 8:04 ` Jay Martin
1995-01-06 0:07 ` Michael M. Bishop
1995-01-10 21:30 ` Jay Martin
replies disabled
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox