Re^8: Finding repeat sequences.

[DamianConway]

So you try to predict the future; ie, guess.

No. I simply try to develop coding habits that make the inherently unpredictable nature of the future less error-prone and less fraught. Basing those habits on repeated patterns of behaviour and outcome I have identified from observing the past.

I'm very firmly of the opinion -- based on my years of experience -- that premature generalisation has cost this industry far more, in both financial and in terms of its reputation for spending a fortune developing huge, all encompassing, singing & dancing solutions that never work, and quietly or otherwise, just end up in the bit bucket; than premature optimisation ever has or ever will.

I'm sure you're right. But you seem to be berating me for something I neither suggested nor advocate.

It didn't prefer the regex solution because it was already more generalized; I preferred it because it was more descriptive (to me), less error-prone (for me), and easier to rework or enhance (by me) should that eventually become necessary.

And I definitely wasn't suggesting premature optimization. After all, I'm not the one who would:

...willingly and knowingly trade the near 3 orders of magnitude performance gain for that task now, against any potential savings against potential future maintenance costs.

;-)

I was merely saying that I believe that code maintainability is generally more important than code performance. Which is why I still prefer the regex-based solution, even through it's three orders of magnitude slower.

I doubt we're ever going to agree on this...which is fine. But I'm certainly not going to apologize for making maintainability my own higher priority, nor for advocating it as a priority for most developers.

Damian

[BrowserUk]

No. I simply try to develop coding habits that make the inherently unpredictable nature of the future less error-prone and less fraught.

Translation: You expend extra energy now, to potentially save energy in the future. That is guessing!

And if you guess wrong; you didn't just waste that extra energy; you potentially cost more energy undoing the product of that extra energy in order to accommodate the real future requirement.

No matter how you dress that equation in "experience", there is no way to make doing something now that you didn't need to do; in order to potentially save some immeasurable amount of effort that you might need to expend in the future; balance. Never has, and never will.

I'm sure you're right. But you seem to be berating me for something I neither suggested nor advocate.

Certainly not "berating". A frank exchange of views for the purpose of perhaps modifying our positions. (NB: Our own, not each others.)

I assume it is of some interest to you, as you are still taking part.

I was merely saying that I believe that code maintainability is generally more important than code performance. Which is why I still prefer the regex-based solution, even through it's three orders of magnitude slower.

This makes no sense to me.

It implies (not states) that you would condemn (strong word for effect) the users of the application to waiting 4 1/2 weeks instead of 1 hour; 15 weeks instead of 1 day; for the sake that this piece of code might need to be modified at some unspecified time in the future.

As a purely academic nicety, stating that you favour maintenance over performance is always a vote winner; but in the real world, code that does what it needs to do in a timely fashion is of far more importance than whether it was written in a declarative or functional style; or even if it might require the programmer to expend some effort to (re-)understand it in 6 months or 2 years from now.

Indeed, most users would say: "That's his damn job"!

Beyond old-farts like me playing 1stP shooters; I've never heard a user say he wishes his application ran more slowly.

It is the height of something for programmers to favour (potentially) saving a little of their time (for which they are well paid), in a future that may never arrive, over the time of the users who are generally paying (directly or otherwise) for the privilege of using the application.

[DamianConway]

You expend extra energy now, to potentially save energy in the future.

Not really. It was vastly easier for me to code—and then improve—the regex-based approach than it was to even understand the index()-based one. In fact, in this instance, both solutions I submitted had worked perfectly first time. It doesn't get much lower-energy than that.

And, for me, that's the entire point of developing good coding practices and habits: once you have them, they require far less work initially, and (if you choose them carefully) they also lead to far less work in the long term.

No matter how you dress that equation in "experience", there is no way to make doing something now that you didn't need to do; in order to potentially save some immeasurable amount of effort that you might need to expend in the future; balance.

I'm sure you wouldn't write that unless you truly believed it. But, if you truly believe it, then there really isn't anything more to discuss. I cannot recall reading a statement about code development and maintenance that accords less well with virtually every experience I have had myself. Nor one with which I would more fundamentally disagree.

Doing something now that you didn't need to do; in order to potentially save an immeasurable amount of effort in the future...that, in my view, is the very essence of good software engineering.

Damian

[BrowserUk]

Doing something now that you didn't need to do; in order to potentially save an immeasurable amount of effort in the future...that, in my view, is the very essence of good software engineering.

You need to look up: Definition of IMMEASURABLE. : incapable of being measured; Which means that none (or negative saving) is equally possible as positive gains.

Then you need to study history. Start with recent history: http://www.theregister.co.uk/2013/06/07/bbc_ignored_dmi_warnings/, http://www.theregister.co.uk/2011/09/20/fire_service_469_million_flop_caused_by_it_illiteracy/, http://www.theregister.co.uk/2010/10/07/depts_dumped_deals_mod/, http://www.theregister.co.uk/2010/09/09/nhs_tech_stopped/, http://www.theregister.co.uk/2010/05/30/scr_review_call/, http://www.channelregister.co.uk/2010/03/22/dft_it_scrapped/, http://www.channelregister.co.uk/2009/07/17/scope_two_cancelled/ ...

The common theme in most of those, and almost all large projects cancelled after large expenditure of time effort and money, is taking 5 years to write software, planning for a life of 15+ years when the requirements will change out of all recognition in 3.

Those are UK because that's what I'm most familiar with, but I know the US government and military IT procurement history is no better. Always overreaching; trying to predict the future and plan for eventualities that will never arise.

And commerce -- global and local -- is equally strewn with IT projects that overreached their psychic powers and failed dismally when the future threw up everything except what their guts told them would come.

“Those who don't know history are doomed to repeat it.”

I have to stop now we've reached the magical re:10 limit.