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Comment by DC-3 | Hacker News Reader

What type of parser does this produce?

For now, it produces a recursive descent parser. Packrat parsing is an open-question since I'm afraid that adding a memoization layer all throughout the parser will lead to a consistent general slowdown.

Interesting. I'll try and find some time to read the source - am interested to see how this is implemented.

A good place to start would be in the manually written example. [1] My current plan is to try and limit the the use of memoization such that it still guarantees linear parsing, but it doesn't memoize unless necessary.

[1]: https://github.com/pest-parser/pest/blob/master/pest/example...

I appreciate the link - I'm teaching myself about parsers right now and like the rest of HN I like Rust programs ;)

"Parsing expression grammars (PEGs) are an alternative to context free grammars for formally specifying syntax" [1]

Basically, you have tools for context free grammars such as GNU Bison or Yacc. This is an alternative, but with PEG.

For more in-depth info, there's the original PEG paper. [2]

[1]: http://bford.info/packrat [2]: http://bford.info/pub/lang/peg

That's the grammar, not the parser resulting from the grammar.

The README doesn't say, but most PEGs in the wild (AFAICT) compile down to / are implemented by packrat parsers.

With PEGs (like Pest), it's probably going to be a packrat parser (which would also make sense given the project's name).

Thank you for the actual answer. Funny how some people are so excited to give an RTFM answer that they forget to read the question.

E: turns out this is wrong anyway.

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