This project by Chris Milne and Nick Castle extends our class homework 4 by adding
in exception handling. For our checkpoint we have added the structure for Error,
Try, and Raise into the end of the step and infer functions, which are all exception
handling. We have also added Error, Try, and Raise as an exp type. Currently we have
each expression type as raising "TODO" errors so that we know that they must still
be implemented. We changed the name of hw4.ml to finalProject.ml and all of our work
so far is in that file.


Build Instructions: (David Durais)

Make sure you have ocaml 4.06.0, and ppx_deriving installed.

    > opam switch 4.06.0
    > opam install ppx_deriving

There are two special files in this directory which help merlin and ocamlbuild
know how to build the project.

First, there is a hidden file .merlin which instructs merlin to:
1. find source files in this directory
2. find build files in the _build directory
3. use the ppx_deriving.std package when checking files

Next, there is a special file _tags which instructs ocamlbuild to:
1. use the ppx_deriving.std package when compiling files

There is an included Makefile that will build all *.ml files in the current
directory as the default target:

    > make

If you want to execute a file, for example, finalProject.ml, just execute:

    > make finalProject

Running either of these commands will generate a bunch of compiled files. These
will get placed in the _build directory, and that directory will be created
automatically if it doesn't already exist. To get rid of the _build directory,
just execute:

    > make clean