OCaml CAS

Quick Start

OCaml CAS requires the opam packages async, base, core.

To get started, run

dune exec -- ./main.exe <port>

and to connect, (if you have nc installed), run

nc localhost <port>
> 3+4
7.
> ...

Project Layout

Most of the project lies within the ./cas directory.

cas
├── expr
│   ├── dune
│   ├── expr.ml
│   └── expr.mli
├── parser
│   ├── dune
│   ├── parser.ml
│   └── parser.mli
├── repl
│   ├── dune
│   ├── engine.ml
│   ├── engine.mli
│   ├── eval.ml
│   ├── eval.mli
│   ├── repl.ml
│   ├── repl_state.ml
│   └── repl_state.mli
└── tokenizer
    ├── dune
    ├── tokenizer.ml
    └── tokenizer.mli

The parser and tokenizer moduels are used to parse input strings into syntax trees. The expr module defines an expression tree and a function to convert a syntax tree into an expression tree. Finally, the repl module contains eval.ml, which takes an expression tree and evaluates it.

Extending Functionality

• To add a new function or constant, simply add it into repl_state.ml (with the right classification of Function or Constant), and in the eval.ml module, implement how it should be evaluated.

• To add a new gramamr rule, go into parser.ml and modify the get_substitution function to add a new grammar rule. The available substitutions are defined in type substitution. If a new substitution type is added, make sure to implement how it should be matched in the perform_sub function (as well as how the resulting syntax tree should be constructed).

Future Work

• Support user defined constants and functions
• Symbolic calculations (partially implemented)
• Integrate arbitrary precision numbers
• Expression tree simplifications