Coding Standards. was: a style question

[Jeff d'Arcy]

dbc at bushido.uucp (Dave Caswell) writes:
>rules like having a single entrance and exit point are good
>ones.  They should be written down and strictly enforced.

Blech!  Consider the following example:

int fubar (x, y, z)
int x, y, z;
{
    if (abnormal_condition_1)
	return(foo);
    if (abnormal_condition_2)
	return(bar);
    for (blah; blah; blah) {
	do_some_stuff();
	if (screwed_up)
	    return(foobar);
	do_other_stuff();
    }
    return(blech);
}

If you enforce a single-exit-point rule the code will be obfuscated to a
pretty high degree.  For starters you'd have to declare a dummy return
variable to hold values for the abnormal_condition cases, just so you can
use it at your single exit point.  Then you'd have the entire for loop
encased in an unnecessary extra if statement, contributing to "indentation
creep", that nasty syndrome where the real work in a routine is indented
halfway across the page.  To get rid of the return statement in the for
loop you'd either have to use a break (another no-no) or add a new status
variable, making the loop condition more complex and indenting the bottom
part of the for loop still further.

In short, the handstands you'd have to do to enforce a single-exit-point
rule make the code *less* readable and often less efficient as well even
in simple cases such as this.  I'm rabidly opposed to unconstrained goto
statements, but return, break and continue are controlled enough to be
worthwhile.
--

Jeff d'Arcy, Generic Software Engineer - jdarcy at encore.com
             Ask me if I care. . .maybe I do