texmath-0.12.5: test/writer/mml/mfrac7.test

<<< native
[ EFraction
    NormalFrac
    (EGrouped
       [ EIdentifier "x"
       , ESymbol Bin "+"
       , EIdentifier "y"
       , ESymbol Bin "+"
       , EIdentifier "z"
       ])
    (EGrouped
       [ EIdentifier "x"
       , EPhantom (ESymbol Bin "+")
       , EPhantom (EIdentifier "y")
       , ESymbol Bin "+"
       , EIdentifier "z"
       ])
]
>>> mml
<?xml version='1.0' ?>
<math display="block" xmlns="http://www.w3.org/1998/Math/MathML">
  <mfrac>
    <mrow>
      <mi>x</mi>
      <mo>+</mo>
      <mi>y</mi>
      <mo>+</mo>
      <mi>z</mi>
    </mrow>
    <mrow>
      <mi>x</mi>
      <mphantom>
        <mo>+</mo>
      </mphantom>
      <mphantom>
        <mi>y</mi>
      </mphantom>
      <mo>+</mo>
      <mi>z</mi>
    </mrow>
  </mfrac>
</math>