Balanced recursive match example

match.mjs

#!/usr/bin/env node

// Recursive match example
let input = `$(foo $(bar $(baz) qux) qul $(quz) 1) $(almost lisp`;

const matches  = [];
const stack    = [];
const {length} = input;
for(let i = 0; i < length; ++i){
	let char = input[i];
	let next = input[i + 1];
	if("$" === char && "(" === next)
		stack.push([i++, -1]);
	else if(")" === char){
		const match = stack.pop();
		match[1] = i + 1;
		matches.push(match);
	}
}
console.log(matches);