OpenEuphoria

RE: Major Bug in Interpreter [Attn: Robert Craig]

• Posted by Robert Craig <rds at RapidEuphoria.com> Feb 14, 2005
• 509 views

Derek Parnell wrote:
> However, it does effect some of my code though. I now have to go 
> through it all to catch my use of an undocumented, but reasonable,
> coding practice. Reasonable, because this is how it works in other languages
> that I use.

FYI, there are popular languages like C and C++ which
do *not* define what will happen if you call a function with
side effects in the middle of a statement or expression. 
In something as simple as:
    expr_a + expr_b
C/C++ does *not* define whether expr_a or expr_b is evaluated first.
C/C++ defines expression evaluation order only partially, in terms of 
precedence rules.

In a call to a C function:

   myfunc(expr_a, expr_b, expr_c);

the order of evaluation of the arguments is *undefined* by the language.

x[expr_a] = expr_b;

is the same story.

In these situations, function side-effects can create portability issues
as well as readability issues. If you are going to check your Euphoria
code, you had better also check all the C/C++ code you've ever written for 
this portability bug. See the "ANSI C White Book" Section A7 - Expressions.
It seems to me Ada and some others are pretty much the same.

Regards,
   Rob Craig
   Rapid Deployment Software
   http://www.RapidEuphoria.com