vw's (2000 and newer model years) use a drive by wire system. There is no throttle cable, just a wire. (and yes, I have worked on cars, including a 84 rabbit that had a throttle cable which had to be replaced twice).
1) Not all legacy code is nasty; sometimes it is just hard to follow. Be sure that you understand what the code is supposed to do before recommending a rewrite or starting to rewrite.
2) Write unit tests for the old modules. Try to write these unit tests without looking at the legacy code. Legacy code sometimes has bugs; I have seen legacy code that is bug free on occasion. In order to write a good unit test, the programmer needs to understand what the code is supposed to do instead of what it does or does not do.
3) Unit test the old code. Do not change code that passes the unit test.
4) Use the results of unit testing and the estimated effort to implement the new requirements to convince management that a rewrite is necessary.
There is not a clearcut rule for rewriting, sometimes modifying the existing code is the better way to go.
Slashdot Mirror
vw's (2000 and newer model years) use a drive by wire system. There is no throttle cable, just a wire. (and yes, I have worked on cars, including a 84 rabbit that had a throttle cable which had to be replaced twice).
1) Not all legacy code is nasty; sometimes it is just hard to follow. Be sure that you understand what the code is supposed to do before recommending a rewrite or starting to rewrite.
2) Write unit tests for the old modules. Try to write these unit tests without looking at the legacy code. Legacy code sometimes has bugs; I have seen legacy code that is bug free on occasion. In order to write a good unit test, the programmer needs to understand what the code is supposed to do instead of what it does or does not do.
3) Unit test the old code. Do not change code that passes the unit test.
4) Use the results of unit testing and the estimated effort to implement the new requirements to convince management that a rewrite is necessary.
There is not a clearcut rule for rewriting, sometimes modifying the existing code is the better way to go.