How is the term 'refactoring' used?

ggg has asked for the wisdom of the Perl Monks concerning the following question:

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Re: How is the term 'refactoring' used? by chromatic (Archbishop) on Jun 04, 2004 at 07:23 UTC
Refactoring is like taking a complex mathematical equation and applying transformations to make it simpler. Rewriting is like taking a complex mathematical equation and trying to derive it again so that it's simpler. The latter may work, especially if you understand the problem really well, but there's no guarantee that it'll continue to work at every discrete step.	[reply]
Re: How is the term 'refactoring' used? by neniro (Priest) on Jun 04, 2004 at 05:59 UTC
There was a very nice article about refactoring perl-code on perl.com last year.	[reply]
Re: How is the term 'refactoring' used? by dragonchild (Archbishop) on Jun 04, 2004 at 12:52 UTC
Refactoring and rewriting are similar, in that they both change code that is unmaintainable. And, that's all they have in common. Rewriting is when you take the what a program does and write something from scratch to meet that specification. This requires a lot of work up front with no immediate result. Refactoring is when you take the how a program does and improve it. It is very possible that many refactorings can be proven logically equivalent without ever knowing what the program does. This is the important difference. One can safely refactor some code if one has a test-suite that only returns pass/fail and never know anything more. Rewriting requires more work. ------ We are the carpenters and bricklayers of the Information Age. Then there are Damian modules.... sigh* ... that's not about being less-lazy -- that's about being on some really good drugs -- you know, there is no spoon.* - flyingmoose I shouldn't have to say this, but any code, unless otherwise stated, is untested	[reply]
Re^2: How is the term 'refactoring' used? by ggg (Scribe) on Jun 04, 2004 at 14:14 UTC
Your explaination is very helpful. Thanks! ggg	[reply]
Re: How is the term 'refactoring' used? by pbeckingham (Parson) on Jun 04, 2004 at 13:29 UTC
Refactoring and rewriting are very similar in effect - often refactoring involves rewriting. I believe the difference is in the intent and the scale: refactoring is the intent to improve code, from the smallest scale up - single statement, block or sub. Rewriting tends to be more of a "start again" approach to fixing something, and usually applied to a scale larger than a statement or block. I believe both terms can be used most of the time, but there are folks who strongly believe in XP who have a special meaning for the word refactoring, that implies more than the mere language definition.	[reply]
Re: How is the term 'refactoring' used? by CountZero (Bishop) on Jun 04, 2004 at 06:02 UTC
Not that I have noticed. But then again as a non-native speaker of English, it may have totally escaped my attention. :-) CountZero "If you have four groups working on a compiler, you'll get a 4-pass compiler." - Conway's Law	[reply]