<<< native
[ EDelimited
    "\10216"
    "\10217"
    [ Right (EIdentifier "\968")
    , Right
        (EDelimited
           "|"
           "|"
           [ Right (EStyled TextScript [ EIdentifier "T" ])
           , Right
               (EDelimited
                  "{"
                  "}"
                  [ Right
                      (EFraction
                         NormalFrac
                         (EIdentifier "\948")
                         (EGrouped [ EIdentifier "\948" , EIdentifier "\981" ]))
                  , Right (EIdentifier "F")
                  , Right (EDelimited "[" "]" [ Right (EIdentifier "\981") ])
                  ])
           ])
    , Right (EIdentifier "\968")
    ]
, ESymbol Rel "="
, ESymbol Bin "\8722"
, EStyled TextNormal [ EIdentifier "i" ]
, EDelimited
    "\10216"
    "\10217"
    [ Right (EIdentifier "\968")
    , Right
        (EDelimited
           "|"
           "|"
           [ Right (EStyled TextScript [ EIdentifier "T" ])
           , Right
               (EDelimited
                  "{"
                  "}"
                  [ Right (EIdentifier "F")
                  , Right (EDelimited "[" "]" [ Right (EIdentifier "\981") ])
                  , Right
                      (EFraction
                         NormalFrac
                         (EIdentifier "\948")
                         (EGrouped [ EIdentifier "\948" , EIdentifier "\981" ]))
                  , Right (EIdentifier "S")
                  , Right (EDelimited "[" "]" [ Right (EIdentifier "\981") ])
                  ])
           ])
    , Right (EIdentifier "\968")
    ]
]
>>> tex
\left\langle \psi\left| \mathcal{T}\left\{ \frac{\delta}{\delta\phi}F\lbrack\phi\rbrack \right\} \right|\psi \right\rangle = - \mathrm{i}\left\langle \psi\left| \mathcal{T}\left\{ F\lbrack\phi\rbrack\frac{\delta}{\delta\phi}S\lbrack\phi\rbrack \right\} \right|\psi \right\rangle