Scaneando formula estequiometrica usando at-script

gistfile1.txt

@isUpperCaseChar(char) => (char.match(#[A-Z]#g#)).size() !== 0;
@isLowerCaseChar(char) => (char.match(#[a-z]#g#)).size() !== 0;
@isNumberChar(char) => (char.match(#[0-9]#g#)).size() !== 0;
@scan(input) {
    let i = 0;
    let multiplier = 1;
    let tokens = [];
    while (i < input.size()) {
        let char = input[i++];
        if (isUpperCaseChar(char)) {
            let name = char;
            if (isLowerCaseChar(input[i])) {
                name += input[i++];
            }
            tokens.push({
                value: name,
                count: 1 * multiplier,
                type: 'atom'
            });
        } else if (isNumberChar(char)) {
            let num = char;
            while(i < input.size() && isNumberChar(input[i])) {
                num += input[i++];
            }
            if (tokens[tokens.size() - 1] &&
                tokens[tokens.size() - 1].type === 'atom'
            ) {
                tokens[tokens.size() - 1].count *= num;
            } else if (input[i] === '(' || isUpperCaseChar(input[i])) {
                multiplier = num;
            }
        } else if (char === ')') {
            multiplier = 1;
        }  else if (char === '+') {
            multiplier = 1;
            tokens.push({
                value: '+',
                type: 'addition'
            });
        } else if (char === '≅') {
            tokens.push({
                value: '≅',
                type: 'equality'
            });
        }
    }
    tokens.push({
        value: null,
        type: 'eof'
    });
    return tokens;
}

print scan('NaOH + ClH ≅ H2O + NaCl');
echo(scan('NaOH + ClH ≅ H2O + NaCl'));