text: const expandAbbreviatedValus = require('../util/expand-abbreviated-values');
  const lengthPercentage = require('../combies/length-percentage');
  const optional = require('../tools/optional');
  const maybe = require('../tools/maybe');
  
  module.exports = maybe(stream => {
      const consumeSide = () => {
          const arr = [];
          for (let i = 0; i < 4; i++) {
              const next = lengthPercentage(stream);
  
              if (next) {
                  arr.push(next);
              } else {
                  break;
              }
          }
  
          return expandAbbreviatedValus(arr);
      };
  
      const left = consumeSide();
      let right = null;
  
      if (!left) {
          return null;
      }
  
      if (optional(stream, 'punc', '/')) {
          right = consumeSide();
  
          if (!right) {
              return null;
          }
      } else {
          right = left;
      }
  
      return {
          type: 'border-radius',
          topLeftRadius: [left[0], right[0]],
          topRightRadius: [left[1], right[1]],
          bottomLeftRadius: [left[2], right[2]],
          bottomRightRadius: [left[3], right[3]]
      };
  });
  