Package customdecode contains a HCL extension that allows, in certain contexts, expression evaluation to be overridden by custom static analysis.

Package dynblock provides an extension to HCL that allows dynamic declaration of nested blocks in certain contexts via a special block type named "dynamic".

Package transform is a helper package for writing extensions that work by applying transforms to bodies.

Package tryfunc contains some optional functions that can be exposed in HCL-based languages to allow authors to test whether a particular expression can succeed and take dynamic action based on that result.

Package typeexpr extends HCL with a convention for describing HCL types within configuration files.

Package userfunc implements a HCL extension that allows user-defined functions in HCL configuration.