A whole bunch of stuff in Phobos (including std.range.Radial and the FFT
algorithm I just checked in) requires that ranges provided to it have
slicing. This limitation is a PITA. Should we add a Slicer meta-range
that takes a finite random-access range and bolts slicing on in the
obvious but relatively inefficient way if it's not already supported and
simply returns the range if it already supports slicing? This would be
used under the hood when slicing is required. For example:
struct Slicer(R) if(isRandomAccessRange!R && !hasSlicing!R) {
R range;
size_t lowerLim, upperLim;
this(R r) {
this.range = range;
this.upperLim = range.length;
}
// Range primitives: front, popFront, etc.
typeof(this) opSlice(size_t lower, size_t upper) {
// Error checking
auto ret = this;
ret.upperLim -= this.length - upper;
ret.lowerLim += lower;
return ret;
}
}
auto slicer(R)(R range) {
static if(hasSlicing!R) {
return range;
} else {
return Slicer!(R)(range);
}
}
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