Re: count and count_if algorithms return type seem to insufficient for large values

Pete Becker <>
Mon, 28 Apr 2008 14:15:00 -0400
On 2008-04-28 13:31:34 -0400, "kwikius" <> said:

Not all containers need to have every element operated on.

In which case they don't have to have iterators.

 lookup is an
example. You don't need to iterate a lookup for its main functionality .

Sigh. You have to be able to look at every element, i.e. "operate on"
every element.

Since there is no description here of how this paradigm works, I can't
assess this assertion.

Its about concepts dealing with one single functionality of a type in
expression rather than monolithic concepts covering large amounts of
functionality ( e.g HasPlus preferred to Arithmetic ) think of eg
ForEachableContainer CountIfAbleContainer etc, like the modern move from
"traits blob" to metafunctions.

I'm sorry, I have no idea what that means.


But the most important point is it removes the necessity of exposing the
blooming iterators in every algorithm, which makes source code less
expressive :

fun(my_container, your_container , f) ; //overloaded or internally

as against

fun(my_container.begin(), my_container.end(), my_container.begin(),
your_container.end(), f) ; //error?

At the cost of having to pretend that the keyboard, for example, is a
container rather than the source of a sequence of characters.

Oh don't get me started on istream.

Who said anything about istream? Regardless, you have to deal with the
issue of pretending that a keyboard is a container.

Simple console input is a lazy list with customisable terminator... eg for
continuous multiline input, disc istream is array or tuple, database istream
a lookup etc...

That's what I said: you have to pretend that the keyboard is a container.

Roundhouse Consulting, Ltd. ( Author of "The
Standard C++ Library Extensions: a Tutorial and Reference

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