What is Parsing Expression Grammar?
Parsing Expression Grammar(PEG) describes a formal languages as a set of rules for recognizing strings in the language.
PEG is somewhat similar to Context Free Grammar(CFG), but the difference is that PEG follows “first match” rule, while CFG is ambiguous.
PEG has a linear-time complexity.
Definition of PEG Parser
Syntax
Somewhat similar to regular expression
- Sequence
e1 e2 - Choice
e1 / e2 - Zero-or-more
e* - One-or-more
e+ - Optional
e? - And-predicate
&e - Not-predicate
!e