Function peg$parseOPTIONAL

packages/graph/src/grammar.js:15804–15839

()

  }

  function peg$parseOPTIONAL() {
    let s0, s1, s2, s3;

    s0 = peg$currPos;
    s1 = input.substr(peg$currPos, 8);
    if (s1.toLowerCase() === peg$c88) {
      peg$currPos += (8);
    } else {
      s1 = peg$FAILED;
      if (peg$silentFails === 0) { peg$fail(peg$e93); }
    }
    if (s1 !== peg$FAILED) {
      s2 = peg$currPos;
      peg$silentFails++;
      s3 = peg$parseIdentifierPart();
      peg$silentFails--;
      if (s3 === peg$FAILED) {
        s2 = undefined;
      } else {
        peg$currPos = s2;
        s2 = peg$FAILED;
      }
      if (s2 !== peg$FAILED) {
        s1 = [s1, s2];
        s0 = s1;
      } else {
        peg$currPos = s0;
        s0 = peg$FAILED;
      }
    } else {
      peg$currPos = s0;
      s0 = peg$FAILED;
    }

    return s0;
  }

  function peg$parseUNWIND() {
    let s0, s1, s2, s3;