b72u68 / arithmetic-expressions

Simple arithmetic expression parser using Ocaml

Arithmetic Expression Parser

Simple arithmetic expression parser using Ocaml

Overview

This project uses Ocaml to parse and evaluate basic arithmetic expression. The operator and expression of this arithmetic expression can be defined as

type binop = Add | Sub | Mul | Pow

and

type expression =
    | Num of float
    | Var
    | Binop of binop * expression * expression
    | Neg of expression

where Num n represents the floating-point number n. Var represents the only variable, which is x. Binop (o, e1, e2) represents a binary operation o between expression e1 and expression e2 where o can be either Add, Sub, Mul, or Pow. And Neg e is the negation of expression e (in this parser, we will implement negation as ~ symbol to remove ambiguity in the language while parsing expression string).

For example, we could represent -3.0x^2 + 2.0 as

Binop (Add, Binop (Mul, Binop (Pow, Var, Num 2.0)), Num 2.0)

Parsing and evalutating only support functions with at most one variable x. Including different variables other than x would raise ParseError.

Installation

This project requires opam Ocaml package management and ocaml installed in your local machine. For more information, visit https://ocaml.org/learn/tutorials/up_and_running.html for instruction on how to install opam and ocaml.

Clone this repository to your local machine

git clone https://github.com/b72u68/arithmetic-expressions

Running

In your shell, run the following command

ocaml

to open the Ocaml shell installed in your local machine. In the Ocaml shell, run #use 'expressions.ml';; to import the file and use it.