Noun
(computing, software compilation) The analysis in advance of subsequent decisions that would be made if a particular branch of an algorithm was followed.
Our computer chess program uses lookahead to avoid difficult endgames.
(regular expressions) The analysis of the subsequent characters before the regular expression is matched.
Source: en.wiktionary.orgA grammar that needs lookahead to disambiguate reductions would require a parse table row containing different reduce actions in different columns, and the above procedure is not capable of creating such rows. Source: Internet
But this minimization is not necessary, and can sometimes create unnecessary lookahead conflicts. Source: Internet
Being a lookahead parser by definition, it always uses a lookahead, with LALR(1) being the most-common case. Source: Internet
Each occurrence of a symbol S in the grammar can be treated independently with its own lookahead set, to help resolve reduction conflicts. Source: Internet
Entries in a table show whether to shift or reduce (and by which grammar rule), for every legal combination of parser state and lookahead symbol. Source: Internet
For each nonterminal S, the SLR generator works out Follows(S), the set of all the terminal symbols which can immediately follow some occurrence of S. In the parse table, each reduction to S uses Follow(S) as its LR(1) lookahead set. Source: Internet