pyparsing VS Lark

After over a year since the last release of pyparsing, I've bundled up all the bug-fixes and changes, and they are now released as pyparsing 3.1.0. Visit this link for the details.

Look into "parser combinators" for building an interpreter. There's a few ones out there, but PyParsing is one I've seen around that looks pretty nifty.

I havent found a way to specify an exact character match in pyparsing - https://github.com/pyparsing/pyparsing/discussions/443

STDOUT: Lark or pyparsing

Since it is not mentioned in the article: Python users may also want to check out pyparsing [0]. It is slightly different from Parsec/FParsec (for instance, it ignores all whitespace by default), but I think it is a really good project.

[0]: https://github.com/pyparsing/pyparsing/

Here is the page of all the new changes and features in pyparsing 3.0.

Your pyparsing parser might benefit from a tune-up. This page has some performance tips: https://github.com/pyparsing/pyparsing/wiki/Performance-Tips.

If your SQL has fairly complex structure, you will need a full blown SQL parser. If your statements are mostly simple select, you can get pretty close with Pyparsing, here is an example.

Lark supports, and recommends, writing and storing the grammar in a .lark file. We have syntax highlighting support in all major IDEs, and even in github itself. For example, here is Lark's built-in grammar for Python: https://github.com/lark-parser/lark/blob/master/lark/grammar...

You can also test grammars "live" in our online IDE: https://www.lark-parser.org/ide/

The rationale is that it's more terse and has less visual clutter than a DSL over Python, which makes it easier to read and write.

First, let me introduce myself. My name is Erez. You may know some of the Python libraries I wrote in the past: Lark, Preql and Data-diff.

It's not super maintained but you might enjoy building something with ppci, Pure Python Compiler Infrastructure. It has some front-ends and some back-ends. There's also PeachPy for an assembler. People like using Lark for parsing, I hear.

lark, a parsing library where I am somewhat involved has a really nice solution to this: Rules starting with _ are inlined in a post processing step.

Lark is a good library to assist with this.

If I may ask, did you consider Lark, and if so, why wasn't it fit for your purposes?

A grammar provides the high level constructs you need to define the "shape" of your data, and it largely takes care of the rest. Grammar libraries exist in other language (eg. lark or Parsimonius in Python) and they weren't created just to make XML parsing easier.

I made a solid attempt at an Earley parser framework of my own, but apparently to get the most reliable performance from Earley parsing you need to implement Joop Leo's improvement for right-recursive grammars, which nobody has been able to adequately explain to me. I've read Kegler's open letter to Vaillant, I've tried to read other implementations, I've even tried to beat my head against the original academic paper, but I don't have the background knowledge to make sense of it all.