<<< native
[ EUnder
    True
    (EMathOperator "lim")
    (EGrouped
       [ EIdentifier "z"
       , ESymbol Rel "\8594"
       , ESub (EIdentifier "z") (ENumber "0")
       ])
, EIdentifier "f"
, EDelimited "(" ")" [ Right (EIdentifier "z") ]
, ESymbol Rel "="
, EIdentifier "f"
, EDelimited
    "(" ")" [ Right (ESub (EIdentifier "z") (ENumber "0")) ]
]
>>> mml
<?xml version='1.0' ?>
<math display="block" xmlns="http://www.w3.org/1998/Math/MathML">
  <mrow>
    <munder>
      <mo>lim</mo>
      <mrow>
        <mi>z</mi>
        <mo>→</mo>
        <msub>
          <mi>z</mi>
          <mn>0</mn>
        </msub>
      </mrow>
    </munder>
    <mi>f</mi>
    <mrow>
      <mo stretchy="true" form="prefix">(</mo>
      <mi>z</mi>
      <mo stretchy="true" form="postfix">)</mo>
    </mrow>
    <mo>=</mo>
    <mi>f</mi>
    <mrow>
      <mo stretchy="true" form="prefix">(</mo>
      <msub>
        <mi>z</mi>
        <mn>0</mn>
      </msub>
      <mo stretchy="true" form="postfix">)</mo>
    </mrow>
  </mrow>
</math>