___           _____  ____  __
                     | _ \__ _ _ _ / __\ \/ /\ \/ /
                     |  _/ _` | '_| (__ >  <  >  <
                     |_| \__,_|_|  \___/_/\_\/_/\_\

ParCXX is a parser combinator library to allow writing parser by composition in a declarative style. It's built following the monadic parser pattern.

Copy the content of src in your code, and include parsec.h.

A parser is a function that takes a beginning iterator and an end iterator, and returns an optional that is either

• Nothing
• A pair of a value and an iterator to what remains to be parsed

Several combination operators are available (a and b are parsers, f is a function):

• a & b parses a then b and if both of them succeeds, returns a pair (result of a, result of b)
• a >> b parses a then b and if both of them succeeds, returns only the result of b
• a << b parses a then b and if both of them succeeds, returns only the result of a
• a >>= b monadic bind operator
• a % f runs a and if it succeeds, applies f on the value returned
• a | b runs a and stops if it succeeds. If it fails, it runs b.
• parse_while(a, x, f) runs a until it fails then folds all the results with f starting with x
• parse_while1 same as parse_while but forces at least one instance of a to exist.
• !a allows a to be present or not. It returns an optional.

Just look at the tests, it should be kinda clear enough.

Examples

Real world usages: A Synthesizer scripting language

Performance note: I found clang++ -std=c++14 -O3 to generate very very performant code. For instance parse_uint(), despite all the crazy lambdas and combinators etc, is resolved into a very simple assembly loop very similar to what would be produced by a handwritten atoi(). Be fearless if you enable optimizations. g++ was not as good though.