The match statement was introduced in Python 3.10, but has not yet seen wide adoption.

In this talk, I'd like to showcase a few more advanced use cases to demonstrate it's expressiveness and versatility, compared to classic parsers using if-elif-else chains, in the hope of attracting a few more Python users to the new concept in Python.

We will have a look at parsing JSON, XML and ASTs, and also compare performance to the classic parsing strategy.

Knowledge of how the match statement works and familiarity with at least one of JSON, XML and ASTs are prerequisite for this talk.

The various match_*.py files have the examples used in the talk and include some extra informmation and code as well, which did not fit the talk.

The bench_match.py file defines define micro benchmarks used in the talk. This is based on the micro_benchmark.py module, which will soon be released as separate package on PyPI. Development for this is taking place in the GitHub - eGenix/egenix-micro-benchmark: Micro benchmark tooling for Python repo, in case you are interested.

Here's a quick example to showcase how easy it is to write micro benchmarks using this new package:

import micro_benchmark

def bench_match_int():
    # Init
    obj = 1
    # Bench
    match obj:
        case float():
            type = 'float'
        case int():
            type = 'int'
        case _:
            pass
    # Verify
    assert type == 'int'

if __name__ == '__main__':
    micro_benchmark.run(globals())

Then run this using Python and see immediate results:

> python3 bench_example.py
.....................
bench_match_int: Mean +- std dev: 107 ns +- 5 ns

The micro benchmark package uses the pyperf package to run the benchmarks, so you get all options and features available with perf (plus a few more), to work with these results.

PDF slides of the talk are available for download:

• PyDDF-Talk-Advanced-Parsing-with-Match-Statement-2024-04-17.pdf is the PDF with the version which was presented at the Python Meeting Düsseldorf on 2024-04-17.

  • This has a few minor errors corrected which were found during the talk.

• PyCon-Italia-2024-Talk-Advanced-Parsing-with-Match-Statement.pdf points to the (current draft) version of the talk which will be presented at PyCon Italia 2024 on 2024-05-25.

These are released under the same license as the other files in this directory.

This talk was or will be held at the following events:

• Python Meeting Düsseldorf on 2024-04-17
• PyCon Italia 2024 on 2024-05-25

For inquiries related to the talk, please write to [email protected] or contact Marc-André Lemburg at [email protected].