Writing your own components

NEAL is written in OCaml, and all the plugins must have at least a thin OCaml compatibility layer.

Currently, there are two kinds of components:

• Reporters
• AST Providers

Compiling and loading components

Components are loaded at runtime, depending on the configurations provided to NEAL, i.e. you shouldn’t need to recompile anything in order to switch or add a new AST Provider. In order to achieve that, plugins must be shared as .cmxs files, which are OCaml dynamic libraries.

All the components released with NEAL (and NEAL itself) are built with Ocamlbuild, which really simplifies the build configuration. Although using Ocamlbuild to build your components is in no way required, I’ll describe it here as it’s standard way components are built throughout NEAL.

Building you component with Ocamlbuild

First, make sure you have OPAM installed:

$ brew install opam

Next you’ll need to install both NEAL and Ocamlfind:

opam install neal ocamlfind

Now, supposing you have your component code in a file component.ml, you can build you component using the following command:

$ ocamlbuild -use-ocamlfind -package neal component.cmxs

Lastly make sure to add the appropriate suffix to your component as describe in the manuals for reporters and AST providers, e.g. if you are building a custom reporter:

$ cp _build/component.cmxs component.reporter.cmxs