Function parseAdditive

src/prolog/parser.js:89–98

()

  }

  function parseAdditive() {
    let node = parseMultiplicative();
    while (peek() && peek().type === 'sym' && (peek().value === '+' || peek().value === '-')) {
      const op = peek().value;
      eat('sym', op);
      const right = parseMultiplicative();
      node = { type: 'expr', op, left: node, right };
    }
    return node;
  }

  function parseMultiplicative() {
    let node = parsePrimary();