Incremental is a library that gives you a way of building complex computations that can update efficiently in response to their inputs changing, inspired by the work of Umut Acar et. al. on self-adjusting computations. Incremental can be useful in a number of applications, including:

• Building large calculations (of the kind you might build into a spreadsheet) that can react efficiently to changing data.
• Constructing views in GUI applications that can incorporate new data efficiently.
• Computing derived data while guaranteeing that the derived data stays in sync with the source data, for instance filtering or inversing a mapping.

You can find detailed documentation of the library and how to use it in incremental/src/incremental_intf.ml. You can also find an informal introduction to the library in this blog post and this video.