Re: "Subtract C, add Ada"

[milod@netcom.com (John DiCamillo)]

gasser@masg1.epfl.ch (Laurent Gasser) writes:

>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 choic 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.

>I never saw a good reason for allowing this.

Huh? It falls naturally out of two other C rules:

1) an assignment is an expression whose value is equal
   to that of the thing being assigned,
2) any expression that evaluates to integer 0 is false,
   all other expressions are true.

C would have required a special restriction to prevent
assignment in an if-test.  (Note that assignment in a
loop-test is a useful and common idiom in C.)

That said, if this error is anyone's biggest concern
about developing software in C, then that person has
not really tried to develop software in C.  All lan-
guages have warts, even Ada.

-- 
    ciao,
    milo
================================================================
    John DiCamillo                        Pinin' for the fjords?
    milod@netcom.com                  What kind of talk is that?