math_expression_parser is both an executable binary that can be run, and a library that can be used in Rust programs.

Installing the command-line executable

Assuming you have Rust/Cargo installed, run this command in a terminal:

cargo install math_expression_parser

It will make the math_expression_parser command available in your PATH if you've allowed the PATH to be modified when installing Rust. cargo uninstall math_expression_parser uninstalls.

Adding `math_expression_parser` library as a dependency

Run this command in a terminal, in your project's directory:

cargo add math_expression_parser

To add it manually, edit your project's Cargo.toml file and add to the [dependencies] section:

math_expression_parser = "0.1.2"

The math_expression_parser library will be automatically available globally. Read the math_expression_parser library documentation.

Back to the crate overview.

Readme

Math expression parser

Main idea of parses that it will take lines of text from .txt file as input, extract mathematical expressions from it, calculate them, and output the results in "res.txt" file. Parser will be able to work with basic operations, trigonometrical functions, exponential functions (may be more in future)

Code example

use clap::{Arg, Command, builder::PathBufValueParser};
use math_expression_parser::parse_and_eval;
use std::path::PathBuf;

fn main() -> anyhow::Result<()> {
    //here should be your code that gets path to input file. Example (using clap):
    let matches = Command::new("Math Expression parser")
        .version("1.0")
        .author("Nazar Sydorchuk <n.sydorchuk@ukma.edu.ua>")
        .about("Parses and evaluates mathematical expressions from a file")
        .arg(
            Arg::new("file")
                .short('f')
                .long("file")
                .help("Path to the input file containing the mathematical expression")
                .value_parser(PathBufValueParser::new()),
        )
        .get_matches();

    let file_path: &PathBuf = matches.get_one("file").expect("No file path provided");
    let input = std::fs::read_to_string(file_path)?;
    let lines: Vec<&str> = input.lines().collect();
    for input in lines {
        parse_and_eval(input)?;
    }
    Ok(())
}

Output example

((((exp(1)/pow(2,3))-sin(log(100, 10)))+(cos(ln(7.5))*tan(45)))) = -1.2654508780369933
((3+4)) = 7

Grammar

WHITESPACE = _{ " " | "\t" | "\n" | "\r" }
num = { ASCII_DIGIT+ ~ "." ~ ASCII_DIGIT+ |  ASCII_DIGIT+ }
plus = { "(" ~ expression ~ "+" ~ expression ~ ")" }
minus = { "(" ~ expression ~ "-" ~ expression ~ ")" }
multiply = { "(" ~ expression ~ "*" ~ expression ~ ")" }
divide = { "(" ~ expression ~ "/" ~ expression ~ ")" }
sin = { "sin" ~ "(" ~ expression ~ ")" }
cos = { "cos" ~ "(" ~ expression ~ ")" }
tan = { "tan" ~ "(" ~ expression ~ ")" }
exp = { "exp" ~ "(" ~ expression ~ ")" }
pow = { "pow" ~ "(" ~ expression ~ "," ~ expression ~ ")" }
root = { "root" ~ "(" ~ expression ~ "," ~ expression ~ ")" }
log = { "log" ~ "(" ~ expression ~ "," ~ expression ~ ")" }
ln = { "ln" ~ "(" ~ expression ~ ")" }
expression = { num | plus | minus | multiply | divide | sin | cos | tan | exp | root | pow | log | ln }
input = { SOI ~ expression ~ EOI }

Installing the command-line executable

Adding math_expression_parser library as a dependency

Adding `math_expression_parser` library as a dependency