install_parser : string * (lexcode list -> preterm * lexcode list) -> unit

SYNOPSIS: Install a user parser.
DESCRIPTION: HOL Light allows user parsing functions to be installed, and will try them on all terms during parsing before the usual parsers. The call install_parser(s,p) installs the parser p among the user parsers to try in this way. The string s is there so that the parser can conveniently be deleted again.
FAILURE CONDITIONS: Never fails.
SEE ALSO: delete_parser, installed_parsers, try_user_parser.