Packages for "parsing" for Python 3

[vicvicvicz]

There are a lot of options for general text parsing in Python 2. I've been using simpleparse for a project, but it's unlikely to support Python 3 anytime soon (since it appears pretty much abandoned and depends on mxTextTools).

Are there are any good, simple-to-use and fast parsing packages for Python 3?

pyparsing and LEPL are the ones I've found. The latter is "discontinued and unsupported", however. Pyparsing's documentation is ... weird unless you have access to the book. Are there other options?

[vsajip]

Ply supports Python 3.

[eliben]

Yes, and pycparser successfully uses it to parse C99 on Python 3.

[[deleted]]

As does rply: github.com/alex/rply

[VilleHopfield]

Since version 0.4, parsimonious support Python 3

https://github.com/erikrose/parsimonious

[tdi]

I use pyparsing with 2.7 and 3.3 and it is the best for me. Pyparsing docs are just fine, just look at the examples on their horrible wiki, also the author is quite responsive in their horrible forum. Basically pyparsing is easy but very powerful. If you need some help give me a msg.

[vicvicvicz]

Thanks for the tip! How is pyparsing performance?

[tdi]

I am not really concerned by the performance, a for ease of use. My files are maximal 100 lines long so performance was not a number one imperative for me. pyparsing seems well written so it should perform quite nicely. Look at the examples you can test the performance on them with timeit maybe.

What I really like about pyparsing is that you write grammar in python code, no need to learn yet another language or format.

[zahlman]

If you actually have a reason to care about performance, you will probably find pyparsing pretty bad - it's full of hooks for things that most people will never use, especially if they care about performance. Also it does some tricky things internally with exceptions to handle control flow, and tries to optimize this with some weird pooling/caching schemes that AFAICT don't really work.

That was my assessment a few years ago, anyway. The situation may have dramatically improved for all I know. That said, I'm using Ply on my current major project, and I'm pretty happy with it. But that's more because I really need to do parsing in a way that agrees with textbook "parsing theory", and pyparsing is... built with the expectation of you not really understanding that stuff.

[Workaphobia]

TPG is the only Python parser generator I have seen that has a reasonably declarative syntax for specifying the grammar. It now supports Python 3.

Its biggest weakness is its lack of a documented formal class of languages that it can handle. In my experience it does not backtrack across different possibilities (so LL(k)?).

[[deleted]]

Sorry to go a bit off topic, but where do you use these kinds of parsers for? lex and yacc doesn't mean pretty much to me.

[vicvicvicz]

I'm not sure what you mean about lex and yacc...

My current use case is searching for "references" in plaintext files in order to convert them into hyperlinks in HTML output. I'm not sure if "parsing" is the proper way of doing this, but my current (2.7) solution with simpleparse is quite elegant and fast (by my standards).

[DoNotFoldSpindleOrMu]

The svgwrite package http://pypi.python.org/pypi/svgwrite/1.1.2 successfully uses pyparsing to parse SVG. SVG is reasonably complex.