There is a BIG difference between Lua Fun and Underscore. Lua Fun is based on iterators. High-order functions such as map, filter, etc. don't create temporary tables and don't allocate extra memory. Since all operations are performed on the fly during iteration, most expressions use constant amount of memory to evaluate.

Looks cool, but hasn't been updated in four years.

mirven does seem to have gone quiet (on Github & Twitter).

Two more up-to-date forks can be found here....

- https://github.com/jtarchie/underscore-lua

- https://github.com/mark-otaris/underscore.lua

NB. The jtarchie fork seems best because its got 59 stars & 5 contributors.