balance: A Go repository from enescakir

A package for validating the balance of parentheses

Getting started

Install balance:

$ go get github.com/enescakir/balance

Add balance to your imports to start using

import "github.com/enescakir/balance"

Usage

`Check(str string) (valid bool, err error)`

It checks given string for parentheses balance for {}, (), [] pairs

valid, err := balance.Check("{()[]}(())")
// Returns: valid => true, err => nil

valid, err := balance.Check("([)]")
// Returns: valid => false, err => MismatchError

valid, err := balance.Check("[[]")
// Returns: valid => false, err => UnclosedParenthesesError

valid, err := balance.Check("({a})")
// Returns: valid => false, err => UnknownCharacterError

`CheckCustom(str string, opens string, closes string) (bool, err)`

It checks given string for parentheses balance for custom pairs.

opens and closes strings should have pair elements in same order.

Given pair elements have to be unique. CheckCustom function doesn't work properly without unique elements.

valid, err := balance.CheckCustom("<<>><>", "<", ">")
// Returns: valid => true, err => nil

valid, err := balance.CheckCustom(")))()(((", ")", "(")
// Returns: valid => true, err => nil

valid, err := balance.CheckCustom("<><><>", "<<", ">")
// Returns: valid => false, err => CustomPairError

How It Works

The balance checking algorithm uses stack at the core. The stack is simple First in Last out data structure.

The algorithm iterates over the given string. If it encounters an opening character, pushes the character to stack. On the other hand, if it gets a closing character, pops the top element from the stack and checks them for pairing. Eventually, if they aren't matching pairs, it raises MismatchError. If the encountered character is not a member of either the opening or closing sets, it raises UnknownCharacterError. End of the iteration, the stack should be empty. If not, there is an unclosed parenthesis. So it raises UnclosedParenthesesError

HTTP Server

It's a simple HTTP server that shows example usage for balance package.

It checks parenthesis balance of given string and save request history to memory or MySQL database for calculating some metrics.

Visit server directory for detailed documentation.

Testing

You can use go test method for unit tests.

Test coverage: 100%

Contributing

balance is an open source project run by Enes Çakır, and contributions are welcome! Check out the Issues page to see if your idea for a contribution has already been mentioned, and feel free to raise an issue or submit a pull request.

enescakir/balance