Description:

sl is a memory-efficient generic linked list library. It doesn't use
container nodes. Instead it requires a pointer to the next item
directly in the datastructure you want to create lists (or stacks) of.
This can give you significant memory savings when creating long lists
of small structures. It also allows for fast push and pop operations
since there is no need to allocate or free memory for the container
nodes. It also means that a push can't fail because memory couldn't be
allocated for the container node.