sub-structural sharing after Syntax.check phase, with global interning of logical entities (the latter is relevant when bypassing default parsing via YXML); minor tuning;

low-level tuning;

Table.lookup_key and Graph.get_entry allow to retrieve the original key, which is not necessarily identical to the given one; Sorts.certify_class: prefer the persistent name;

XML.pretty with depth limit;

more thorough Variable.check_name: Binding.check for logical entities within the term language;

tuned;