# i2

> The middleware toolbox


## Pages in this subsection

- [i2](i2.html.md): Meta-programming tools to build declarative frameworks
- [i2.base](i2.base.html.md): Tools to provide meta-interfaces (“mints”) of python objects.
- [i2.castgraph](i2.castgraph.html.md): A lightweight transformation service for Python that solves the “stable role,
- [i2.chain_map](i2.chain_map.html.md): Merge mappings
- [i2.deco](i2.deco.html.md): Decorator tools
- [i2.doc_mint](i2.doc_mint.html.md): Meta-interfaces
- [i2.errors](i2.errors.html.md): Error objects
- [i2.footprints](i2.footprints.html.md): Analyzing what attributes of an input object a function actually uses
- [i2.io_trans](i2.io_trans.html.md): Tools to make input and output transforming decorators.
- [i2.itypes](i2.itypes.html.md): | `dot_string_of_callable_typ`(typ)                   | A `inputs -> Callable -> output` string, wit...
- [i2.key_path](i2.key_path.html.md): Flattening maps and manipulating key paths
- [i2.multi_object](i2.multi_object.html.md): A few fundamental tools to operate on a fixed collection of objects (e.g. functions).
- [i2.routing_forest](i2.routing_forest.html.md): Tools to specify functions through trees and forests.
- [i2.signatures](i2.signatures.html.md): Signature calculus: Tools to make it easier to work with function’s signatures.
- [i2.util](i2.util.html.md): Misc util objects
- [i2.wrapper](i2.wrapper.html.md): A wrapper object and tools to work with it

## Optional

- [Top-level llms.txt](../llms.txt): Complete documentation index.