On Jun 27, 2006, at 3:11 AM, Michael Hawksworth wrote:
The single vs multiple point of exit argument has been going on for
years, made more intense by the arrival of the newer development
theories.
That arose in the days of 'top-down' programming, which was all the
rage when I was in college. When you wrote your code, you created
pseudo-code where you defined your procedures and their return
values, and then you fleshed out the actual code that produced those
return values. Probably the biggest reason for insisting on the "one
entry, one exit" style was the prevalence then of GOTO, which was
abused terribly; this style was a reaction to that 'anything goes'
style and its spaghetti code results.
Personally, I think that what's important is predictable, readable
code. The one exit style is just an attempt at achieving this. But
having a style that checks for conditions at the top of a procedure
and exits if they are not met is a very clear, readable and
maintainable style. In fact, most main methods in Dabo follow the
pattern I added to Codebook methods:
def doSomething(self):
errorCode = self.beforeDoSomething()
if errorCode:
return errorCode
<main code goes here>
self.afterDoSomething()
return resultCode
IOW, every X method has a built-in test: beforeX(), and returning an
error code from that will prevent the rest of the method from
running. Sure, I could have structured it with only one return, but I
don't believe that the code would be better or more readable if I did./
-- Ed Leafe
-- http://leafe.com
-- http://dabodev.com
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