A simple parser for frame sequences strings.
This will parse a [str] describing a sequence of frames into
a [Vec]<[isize]> containing individual frame numbers.
Mainly intended/useful for rendering/animation/VFX applications.
Individual frames:
1,2,3,5,8,13 ⟶ [1, 2, 3, 5, 8, 13]
A sequence:
10-15 ⟶ [10, 11, 12, 13, 14, 15]
With step size:
10-20@2 ⟶ [10, 12, 14, 16, 18, 20]
Step size must be always positive.
To get a sequence backwards specify the range in reverse:
42-33@3 ⟶ [42, 39, 36, 33]
With binary splitting:
10-20@b ⟶ [10, 20, 15, 12, 17, 11, 13, 16, 18, 14, 19]
The last frame of a sequence will be omitted if the specified step size does not touch it:
80-70@4 ⟶ [80, 76, 72]
Using x instead of @ as the step size token separator also works.