tags : Context Free Grammar (CFG), Programming Languages, Parsers, Production Systems
What
- Syntactically, PEGs also look similar to context-free grammars (CFGs), but they have a different interpretation: the choice operator selects the first match in PEG, while it is ambiguous in CFG.
- Unlike CFGs, PEGs cannot be ambiguous; a string has exactly one valid parse tree or none
- Provides unlimited lookahead capability
- An Alternative to Context Free Grammar (CFG)
About PEG Parsers
- See Parsers
- It’s possible to build LL and LR parsers for some PEGs but all PEGs can’t be built using LL/LR because of unlimited lookahead. (NOTE: I don’t understand this properly)
- PEG can be parsed in linear time by using a packrat parser