Termops.InternalSourceNOTE: to print terms you always want to use functions in Printer, not these ones which are for very special cases.
debug printers: print raw form for terms, both with evar-substitution and without.
Pretty-printer hook: print_constr_env env sigma c will pretty print c if the pretty printing layer has been linked into the Coq binary.
set_print_constr f sets f to be the pretty printer
Printers for contexts