link:parsetree.mli[Parsetree] and link:asttypes.mli[Asttypes]::
Parsetree is an Abstract Syntax Tree (AST) representation of OCaml
source code. It is well annotated with examples and is a recommended
read before any further exploration of the compiler.

link:location.mli[Location]:: This module contains utilities
related to locations and error handling. In particular, it contains
handlers that are used for all the error reporting in the compiler.

