Re: Re[2]: IBM pushing Java

Excerpts from midrange-l: 23-Mar-99 RE: Re[2]: IBM pushing Java Tim
McCarthy@softwarejun (831*) 

>       But rewriting old code that does the job can be fraught with 
> bugs. In this debate, rewrite Vs patch, we always underestimate the 
> number of "undocumented features" we'll inevitably introduce. 

Oh, yes, I agree.  "Rewriting old code that does _the job_" doesn't make
*any* sense without some motivating change in the nature of _the job_. 
And, if I understand you correctly, your point that minor changes to
_the job_ may not merit a rewrite is well-taken, indeed. 

However, one point I'm trying to make is:  once some change to _the job_
becomes necessary -- and therefore code changes become necessary --  the
factors affecting the decision of patch vs. rewrite should include the
likelihood and expense of even more changes later.  There's a notion of
'pay-me-now-or-pay-me-later' to some degree, wouldn't you say? 

Take another hypothetical...  If MyModule is so convoluted that I have
to relearn it every time I want to patch it, and it looks like I'll be
patching it fairly frequently, it might make economic sense to start
over and write the function from scratch using a more maintainable
design.  Do I risk adding "undocumented features" such as poorer
performance?  ...or changed behaviors?  ...or broken
backward-compatibility?  You bet.  Risk vs. reward.  Cost vs. benefit. 
Holyfield vs. Lewis. 

BTW, what a nice euphemism -- "undocumented features" -- I'll have to
remember that.  :) 

-blair 

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