lua-users wiki: Filters Sources And Sinks
Certain operations can be implemented in the form of filters. A filter is a function that processes data received in consecutive function calls, returning partial results chunk by chunk. Filters become even more powerful when we allow them to be chained together to create composite filters. Filters can be seen as middle nodes in a chain of data transformations. Sources and sinks are the corresponding end points of these chains. A source is a function that produces data, chunk by chunk, and a sink is a function that takes data, chunk by chunk. In this technical note, we define an elegant interface for filters, sources, sinks and chaining.
Functional programming patterns in Lua