lexpr greater >
lexpr less_equal <=
lexpr greater_equal >=
-lambda pack
-lambda unpack
+lambda list_to_string list->string
+lambda string_to_list string->list
lambda flush
lambda delay
lexpr led
lambda booleanp boolean?
lambda set_car set-car!
lambda set_cdr set-cdr!
+lambda symbolp symbol?
+lambda symbol_to_string symbol->string
+lambda string_to_symbol string->symbol
+lambda stringp string?