tv_stack_frame_stack

t3toolbox.backend.tv_operations.tv_stack_frame_stack(paired_tree)

def tv_stack_frame_stack(
        paired_tree,  # array-like tree (shape G) of (frame_data, variations_data) pairs
):  # -> (
    #        frame-data,       # stack = G
    #        variations-data,  # stack = V + G
    #    )

Stack a G-shaped tree of (frame_data, variations_data) pairs over the frame stack G.

The frame stack is placed innermost (the variation stack becomes V + G), matching the base-inner convention. Takes exactly the paired-tree layout that tv_unstack_frame_stack() produces (its inverse), so a backend user round-trips without splitting the pairs by hand.