Math expression evaluator

Table of content

• Build
• Features
• Usage
• Technologies
• Purpose

Build

run

cargo build --release

Features

• operator precedense
• operator associativity
• nesting
• functions
• function from operator
• pipes
• variables

Usage

for convenience target/release/math-expression-evaluator will be called calc

all whitespace characters are ignored!

to evaluate expression run following

calc "expression"

to use variables specifie them in following format

calc --var <var_name>=<value> "expression"

example

calc --var a=1 --var b=2 "a+b-3"

parentheses are respected

calc "4*(2+3)"

outputs 20 as expected

functions can be used in different ways

classic call (trailing comma is optional)

calc "add(2,5,)"

converting operator to function

calc "(+)(2,5)"

every function is automatically curried

calc "(+)(2)(5)"
calc "add(2)(5)"

pipes syntax is

calc "<value> | <one_arg_function>"

example

calc "2|(+)(4)|(^)(3)"

and it's equal to

calc "3^(2+(4))"

Technologies

• Rust

Purpose

this project was created to learn rust and parsers