Transducers are "composable algorithmic transformations." If you don't know yet what transducers are, there are a few good explanations in this Stack Overflow question.
This is a fairly straightforward implementation of transducers in Lua, but the implementation is not comprehensive. There are many more transducers and transformers that could be implemented. In addition, I only generalize transducers for tables and strings.
I follow, roughly, the transformer protocol outlined in transducers-js.
To run the examples, simply run lua sample.lua -- I used Lua 5.2.3, but any other Lua implementation should work as well.