Arithmetic Eval

Dead simple arithmetic evaluator created for educational purposes. It doesn't use eval() but contains custom tokenizer and evaluator. It correctly handles precedence of operators and parenthesis.

Installation

I didn't provide npm package because it was created solely for educational purposes and has no practical use. But if you want to play with it just run:

# clone repository first
git clone git@github.com:bogdan0083/arithmetic-eval.git
cd ./arithmetic-eval

# to evaluate expression
npx tsx ./bin/cli.ts -e "2 + 2"

# Or you can use `npm link` to create symlink and use the package globaly
npm link
arithmetic-eval -e "2 + 2"

# Here's help output:
arithmetic-eval --help

Usage: arithmetic-eval [options]

Options:
  -e, --expression <exp>  expression to evaluate
  -s, --print-steps       print each step while evaluating (default: false)
  -r, --repl              run interactive repl (default: false)
  -h, --help              display help for command

How does it work?

It first tries to parse symbols as a list of tokens. Then tokens are converted to Postfix notation and finally evaluated.