<?xml version="1.0"?>

    <foo attr="$x"/> Expect '$x'
    <foo attr="val"/> Expect 'val'
    <foo attr="{$x"/> Expect 'bracket $x'
    <foo attr="$x}"/> Expect '$x bracket'
    <foo attr="{$x}"/> Expect 'bracket $x bracket'
    <foo attr="{val}"/> Expect 'bracket val bracket'
  
