Function peg$buildException

lib/parser.js:927–1001

(message, expected, pos)

    }

    function peg$buildException(message, expected, pos) {
      function cleanupExpected(expected) {
        var i = 1;

        expected.sort(function(a, b) {
          if (a.description < b.description) {
            return -1;
          } else if (a.description > b.description) {
            return 1;
          } else {
            return 0;
          }
        });

        while (i < expected.length) {
          if (expected[i - 1] === expected[i]) {
            expected.splice(i, 1);
          } else {
            i++;
          }
        }
      }

      function buildMessage(expected, found) {
        function stringEscape(s) {
          function hex(ch) { return ch.charCodeAt(0).toString(16).toUpperCase(); }

          return s
            .replace(/\\/g,   '\\\\')
            .replace(/"/g,    '\\"')
            .replace(/\x08/g, '\\b')
            .replace(/\t/g,   '\\t')
            .replace(/\n/g,   '\\n')
            .replace(/\f/g,   '\\f')
            .replace(/\r/g,   '\\r')
            .replace(/[\x00-\x07\x0B\x0E\x0F]/g, function(ch) { return '\\x0' + hex(ch); })
            .replace(/[\x10-\x1F\x80-\xFF]/g,    function(ch) { return '\\x'  + hex(ch); })
            .replace(/[\u0180-\u0FFF]/g,         function(ch) { return '\\u0' + hex(ch); })
            .replace(/[\u1080-\uFFFF]/g,         function(ch) { return '\\u'  + hex(ch); });
        }

        var expectedDescs = new Array(expected.length),
            expectedDesc, foundDesc, i;

        for (i = 0; i < expected.length; i++) {
          expectedDescs[i] = expected[i].description;
        }

        expectedDesc = expected.length > 1
          ? expectedDescs.slice(0, -1).join(", ")
              + " or "
              + expectedDescs[expected.length - 1]
          : expectedDescs[0];

        foundDesc = found ? "\"" + stringEscape(found) + "\"" : "end of input";

        return "Expected " + expectedDesc + " but " + foundDesc + " found.";
      }