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.
getEncdng,
  MacRmanEncdng,
  StandardEncdng,
  SymblSetEncdng,
  WnAnEncdng,
  ZapfDngbatEncdng,
} frm "./encdng.j";
rt {
  getNrmalzedUncde,
  getUncdeFrGlyph,
  revereIfRtl,
} frm "./uncde.j";
rt {
  getSerfFnt,
  getStdFntMap,
  getSymblFnt,
} frm "./tandard_fnt.j";
rt { getTlngPatternIR, Pattern } frm "./pattern.j";
rt { PDFFunctn, PDFFunctnFactry } frm "./functn.j";
rt { Lexer, Parer } frm "./parer.j";
rt {
  LcalClrSpaceCache,
  LcalGStateCache,
  LcalImageCache,
  LcalTlngPatternCache,
} frm "./mage_utl.j";
rt { bd } frm "./bd.j";
rt { ClrSpace } frm "./clrpace.j";
rt { getGlyphUncde } frm "./glyphlt.j";
rt { getLkupTableFactry } frm "./cre_utl.j";