Editing LR parser (section)

=== Items ===
<!-- This section is linked from [[LALR parser]] -->

The construction of these parsing tables is based on the notion of ''LR(0) items'' (simply called ''items'' here) which are grammar rules with a special dot added somewhere in the right-hand side. For example, the rule E → E + B has the following four corresponding items:
: E → <big>{{color|#f7f|•}}</big> E + B
: E → E <big>{{color|#f7f|•}}</big> + B
: E → E + <big>{{color|#f7f|•}}</big> B
: E → E + B <big>{{color|#f7f|•}}</big>
Rules of the form ''A'' → ε have only a single item ''A'' → <big>{{color|#f7f|•}}</big>. The item E → E <big>{{color|#f7f|•}}</big> + B, for example, indicates that the parser has recognized a string corresponding with E on the input stream and now expects to read a '+' followed by another string corresponding with B.