Algorithms for Compiler Design: WHY LR PARSING IS ATTRACTIVE

There are several reasons why LR parsers are attractive:

1. An LR parser can be constructed to recognize virtually all programming language constructs for which a CFG can be written.

2. The LR parsing method is the most general, nonbacktracking shift-reduce method known. Yet it can be implemented as efficiently as any other method.

3. The class of grammars that can be parsed by using the LR method is a proper superset of the class of grammars that can be parsed with a predictive parser.

4. The LR parser can quickly detect a syntactic error via the left-to-right scanning of input.

The main drawback of the LR method is that it is too much work to construct an LR parser by hand for a typical programming language grammar. But fortunately, many LR parser generators are available that automatically generate the required LR parser.