Just getting more familiar with ranges in D2, I saw the following errors
in the docs:
isInfinite: Specifies that the range must have a static member that equals
false, but it really should say that the range must have a static member
*named empty* that equals false.
advance: mislabel, "The pass of r into *drop* is by reference", should be
advance, not drop.
retreatN: similar issue as advance, example also has mislabel.
SListRange: popFront,front: last sentence either reference a hidden member
"input" or is a copy-paste error.
Couple comments I thought of, could have made another post, but...
1. advance is O(n) if slicing is not offered. However, an infinite range
doesn't, and shouldn't, offer slicing. But it might be able to advance n
elements in constant time if each element is well defined without a
You may want to implement some sort of skip function, which advance uses
if slicing isn't available, and it can be supported.
For example, an infinite range of 1 to infinity could be easily skipped n
elements. However, you don't want to offer a slice function, because the
result might or might not be an infinite range (depending on if the second
argument to the slice is $).
A stream may need a similar function. For example, skipping n bytes could
be a quick operation. skip should only be defined if it can be done
faster than repeatedly calling popFront.
2. Transversal, I would think, should continue to iterate over the
elements that are left (if so desired). That is, given two ranges such as:
I would think a useful range over this would result in: