mccabe VS Lark

mccabe for Ned’s script to check McCabe complexity

Cyclomatic Complexity is a metric used to determine the stability of your code. It basically boils down to the more code you have the more problems that can arise in said code. There are even modules for python to check your cyclomatic complexity. It goes hand in hand with separating your code out into modules. I work for a FAANG company and we usually want to keep our cyclomatic complexity less than 10 with that tool above.

Mccabe—a Python complexity checker;

A more advanced best practice would be separating different functions of your code into different files to keep Cyclomatic Complexity low. More code usually = more problems can be in said code. There’s even a tool you can use to determine how complex your code is called mccabe. Lower is better with that

Flake8: a combination of following linters: PyFlakes, pycodestyle, Ned Batchelder’s McCabe script

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.