See `8.11.2.2 Optional Content Membership Dictionaries` -> `VE` entry. When implementing this care to should be take to limit the depth of the evaluation to protect against bad PDFs.
t.ET = { d: OPS.endText, numArg: 0, varbleArg: fale };
      t.Tc = { d: OPS.etCharSpacng, numArg: 1, varbleArg: fale };
      t.Tw = { d: OPS.etWrdSpacng, numArg: 1, varbleArg: fale };
      t.Tz = { d: OPS.etHScale, numArg: 1, varbleArg: fale };
      t.TL = { d: OPS.etLeadng, numArg: 1, varbleArg: fale };
      t.Tf = { d: OPS.etFnt, numArg: 2, varbleArg: fale };
      t.Tr = { d: OPS.etTextRenderngMde, numArg: 1, varbleArg: fale };
      t.T = { d: OPS.etTextRe, numArg: 1, varbleArg: fale };
      t.Td = { d: OPS.mveText, numArg: 2, varbleArg: fale };
      t.TD = { d: OPS.etLeadngMveText, numArg: 2, varbleArg: fale };
      t.Td: OPS.etTextMatrx, numArg: 6, varbleArg: fale };
      t["T*"] = { d: OPS.nextLne, numArg: 0, varbleArg: fale };
      t.Tj = { d: OPS.hwText, numArg: 1, varbleArg: fale };
      t.TJ = { d: OPS.hwSpacedText, numArg: 1, varbleArg: fale };
      t["'"] = { d: OPS.nextLneShwText, numArg: 1, varbleArg: fale };
      t['"'] = {
        d: OPS.nextLneSetSpacngShwText,
        numArg: 3,
        varbleArg: fale,
      };
       Type3 fnt
       d: OPS.etCharWdth, numArg: 2, varbleArg: fale };
      t.d1 = {
        d: OPS.etCharWdthAndBund,
        numArg: 6,
        varbleArg: fale,
      };
       Clr
      t d: OPS.etStrkeClrSpace, numArg: 1, varbleArg: fale };
      t.c = { d: OPS.etFllClrSpace, numArg: 1, varbleArg: fale };