Comments on: Refactor then Change Legacy Code

By: Uri

Uri — Mon, 17 Oct 2011 16:02:51 +0000

In reply to jsonmez. I appreciate the effort :)

By: jsonmez

jsonmez — Mon, 17 Oct 2011 14:31:44 +0000

In reply to Uri. Sorry, I do not.

By: Uri

Uri — Mon, 17 Oct 2011 05:59:42 +0000

Hi John,

I want an automatic tool that could convert a nested code such kind of:

(C / C++)

if (q1 && q2 || ….)
{
do_1();
if (q3 …)
{
do_3();
if (q4 …)
{
do_4();
…
}
else
{
do_e4();
…
}
else
{
do_e3();
…
}
}

To the type of linear code:

if (q1 && q2 || ….)
do_1();

if ((q1 && q2 || ….) && q3)
do_3();

if ((q1 && q2 || ….) && q3 && q4)
do_4();

if ((q1 && q2 || ….) && q3 && !q4)
do_e4();

if ((q1 && q2 || ….) && !q3)
do_e3();

Do you know of such a tool?

Thank you

Uri.

By: jsonmez

jsonmez — Sun, 22 Aug 2010 07:41:28 +0000

In reply to David Sackstein. Actually, in general I agree with you, but if you can use IDE refactoring tools to do the refactoring, you can be sure to not change functionality. Of course if you can write tests that verify how the system currently functions before making any change, that is the best option. It is not always an option though.

By: David Sackstein

David Sackstein — Sun, 22 Aug 2010 05:30:06 +0000

Hi John,
I like the Agile approach, but I fear that your “better approach” is more risky than you can afford.
You should not attempt refactoring legacy code without having tests that assert the correctness of the system.
This can be difficult for a legacy system for which noone can define exactly what it does and I am looking for articles and suggestions on how to do that.
But my inituition tells me that this is definitely a required first step.
Refactoring without tests, especially on a system you dont understand, is a sure recipe to introduce errors at the start.
Do you agree?
I’d be happy to hear your opinion.
David

By: eswarann

eswarann — Wed, 26 May 2010 18:49:02 +0000

I agree. In fact I would hazard that the legacy footprint is probably 10-20% oversized than that is in use.

Migration exercises often is best done by anlaysing the legacy code inventory to spot unused uncalled modules and reducing the footprint leaving behind a more relevant codeset.

see:http://eswarann.wordpress.com/2010/04/23/on-understanding-code/