On 07/10/2012 11:41 AM, Jacob Carlborg wrote:
On 2012-07-10 09:09, Jonathan M Davis wrote:
It's a complete failure because not every range works with every
range-based
function? We have isInputRange, isForwardRange, isRandomAccessRange,
hasSlicing, etc. for a reason. Different ranges have different
capabilities, and
different algorithms generate different types of ranges based on what
they do.
For instance, filter cannot possibly have slicing, because it's on O(n)
operation to determine which elements match the predicate. You have to
iterate
through _all_ of the elements. Rather than doing that (and therefore not
working with infinite ranges and being inefficient with non-infinite
ranges), it's
lazy, and if you _do_ want to process all of the elements to know
filter's
length and therefore make it slicable, you generate a new range from it -
generally with std.array.array. map is in the same boat. It has to
generate
new range type, and the choice is between being lazy and efficient (and
therefore require a call to array) or being inefficient and calling array
internally.
Well, I haven't been able to use a single function from std.algorithm
without adding a lot of calls to "array" or "to!(string)". I think the
things I'm trying to do seems trivial and quite common. I'm I overrating
std.algorithm or does it not fit my needs?
If you consider it a problem to call array or to!string when you want
to get an array, then it does not fit your needs.
