Why Strings as Classes?

[superdan]

Nick Sabalausky Wrote:

> "Dee Girl" <deegirl at noreply.com> wrote in message 
> news:g943oi$11f4$1 at digitalmars.com...
> > Benji Smith Wrote:
> >
> >> Dee Girl wrote:
> >> > Michiel Helvensteijn Wrote:
> >> >> That's simple. a[i] looks much nicer than a.nth(i).
> >> >
> >> > It is not nicer. It is more deceiving (correct spell?). If you look at 
> >> > code it looks like array code.
> >> >
> >> > foreach (i; 0 .. a.length)
> >> > {
> >> >     a[i] += 1;
> >> > }
> >> >
> >> > For array works nice. But for list it is terrible! Many operations for 
> >> > incrementing only small list.
> >>
> >> Well, that's what you get with operator overloading.
> >
> > I am sorry. I disagree. I think that is what you get with bad design.
> >
> >> The same thing could be said for "+" or "-". They're inherently
> >> deceiving, because they look like builtin operations on primitive data
> >> types.
> >>
> >> For expensive operations (like performing division on an
> >> unlimited-precision decimal object), should the author of the code use
> >> "opDiv" or should he implement a separate "divide" function?
> >
> > The cost of + and - is proportional to digits in number. For small number 
> > of digits computer does fast in hardware. For many digits the cost grows. 
> > The number of digits is log n. I think + and - are fine for big integer. I 
> > am not surprise.
> >
> >> Forget opIndex for a moment, and ask the more general question about all
> >> overloaded operators. Should they imply any sort of asymptotic
> >> complexity guarantee?
> >
> > I think depends on good design. For example I think ++ or -- for iterator. 
> > If it is O(n) it is bad design. Bad design make people say like you "This 
> > is what you get with operator overloading".
> >
> >> Personally, I don't think so.
> >>
> >> I don't like "nth".
> >>
> >> I'd rather use the opIndex. And if I'm using a linked list, I'll be
> >> aware of the fact that it'll exhibit linear-time indexing, and I'll be
> >> cautious about which algorithms to use.
> >
> > But inside algorithm you do not know if you use a linked list or a vector. 
> > You lost that information in bad abstraction. Also abstraction is bad 
> > because if you change data structure you have concept errors that still 
> > compile. And run until tomorrow ^_^.
> >
> 
> A generic algoritm has absolutely no business caring about the complexity of 
> the collection it's operating on.

absolutely. desperate. need. of. chanel.

> If it does, then you've created a concrete 
> algoritm, not a generic one.

sure you don't know what you're talking about. it is generic insofar as it abstracts away the primitives it needs from its iterator. run don't walk and get a dose of stl.

> If an algoritm uses [] and doesn't know the 
> complexity of the []...good! It shouldn't know, and it shouldn't care.

nonsense. so wrong i won't even address it.

> It's 
> the code that sends the collection to the algoritm that knows and cares. 
> Why? Because "what algoritm is best?" depends on far more than just what 
> type of collection is used. It depends on "Will the collection ever be 
> larger than X elements?". It depends on "Is it a standard textbook list, or 
> does it use trick 1 and/or trick 2?". It depends on "Is it usually mostly 
> sorted or mostly random?". It depends on "What do I do with it most often? 
> Sort, append, search, insert or delete?". And it depends on other things, 
> too.

sure it does. problem is you have it backwards. types and algos tell you the theoretical properties. then you in knowledge of what's goin' on use the algorithm that does it for you in knowledge that the complexity would work for your situation. or you encode your own specialized algorithm.

thing is stl encoded the most general linear search. you can use it for linear searching everything. moreover it exactly said what's needed for a linear search: a one-pass forward iterator aka input iterator.

now to tie it with what u said: you know in your situation whether linear find cuts the mustard. that don't change the nature of that fundamental algorithm. so you use it or use another. your choice. but find remains universal so long as it has access to the basics of one-pass iteration.

> Using "[]" versus "nth()" can't tell the algoritm *any* of those things.

doesn't have to.

> But 
> those things *must* be known in order to make an accurate decision of "Is 
> this the right algoritm or not?"

sure. you make them decision on the call site.

> Therefore, a generic algoritm *cannot* ever 
> know for certain if it's the right algoritm *even* if you say "[]" means 
> "O(log n) or better".

utterly wrong. poppycock. gobbledygook. nonsense. this is so far off i don't have time to even address. if you want to learn stuff go learn stl. then we talk. if you want to teach me i guess we're done.

> Therefore, the algorithm should not be designed to 
> only work with certain types of collections.

it should be designed to work with certain iterator categories.

> The code that sends the 
> collection to the algoritm is the *only* code that knows the answers to all 
> of the questions above, therefore it is the only code that should ever 
> decide "I should use this algorithm, I shouldn't use that algorithm."

correct. you just have all of your other hypotheses jumbled. 

sorry dood don't be hatin' but there's so much you don't know i ain't gonna continue this. last word is yours. call me a pompous prick if you want. go ahead.