RFC: Python-like slices in vec #1799
Description
I would like to modify the vector (and string, I suppose) slicing routines to be more "Python-like". This means that they are more lenient of invalid indices and they consider negative numbers to count from the right.
All in all I propose six functions:
vec::islice(v, from, to) // equivalent to v[from:to] in Python
vec::islice_from(v, from) // equivalent to v[from:] in Python, or vec::slice(v, from, vec::len(v))
vec::islice_to(v, to) // equivalent to v[:to] in Python, or vec::slice(v, 0, to)
vec::uslice(v, from, to)
vec::uslice_from(v, from, to)
vec::uslice_to(v, from, to)
The i family accepts signed integers: negative inputs are considered as counting from the right. The u family takes unsigned integers. All of them are tolerant of invalid indices, returning empty list rather than failing, as Python does. In my experience this is usually what you want.