Orchid XP v8 <voi### [at] devnull> wrote:
> > What if you want to apply it to only a sub-range inside
> > the data container rather than to the entire container? (Can you do it
> > without copying the sub-range to a separate container?)

> Notionally, no.

> Physically? Ask the optimiser.

  One thing which bothers me with haskell is the amount of features which
rely solely on the compiler being able to optimize them. For example a
simple thing like "go through this subrange inside this list and calculate
the sum of the elements", which you usually do in-place, becomes something
which at the language level requires copying (needlessly) the subrange just
so that you can traverse it, and hoping that the compiler will be able to
figure out what is it that you are really doing and optimizing the copying
away.

  In other words, you would have to know the internal workings and
capabilities of the specific compiler you are using in order to know
if you can do it or if you have to do it by other more difficult means
(if copying the range of elements would be way too heavy and memory
consuming to be feasible).

  I don't know... This kind of defeats the whole purpose of a high-level
language where you are supposed to not to have to worry about internal
implementation details of the compiler.

-- 
                                                          - Warp

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