Editing LR parser (section)

=== Closure of item sets ===

Thus, any set of items can be extended by recursively adding all the appropriate items until all nonterminals preceded by dots are accounted for. The minimal extension is called the ''closure'' of an item set and written as '''clos'''(''I'') where ''I'' is an item set. It is these closed item sets that are taken as the states of the parser, although only the ones that are actually reachable from the begin state will be included in the tables.