peter krupa dot lol

I finally “finished” my first major Python application the other day. It’s an RSS reader you can use to parse large lists of RSS feeds, filter for keywords, and save the results to an HTML file for viewing in a browser.

After spending easily a month building a console-based text command user interface for this thing, it just dawned on me, “I bet there’s already a module for this.” Yep, Cmd. So two things about that.

First, it’s a great example of a major failure for Google and a major success for ChatGPT. Initially, I thought what I needed was a “command line interface,” so I did some extensive googling for that and all I came up with was stuff like argparse, which allows you to run Python programs from the command line with custom arguments (home:~$ python3 myscript.py [my_command]). Not finding anything useful, I went on to build what I actually needed, which is a “line-oriented command interpreter.”

The problem with Google is it’s hard to find things when you can describe them, but don’t know what they’re called, especially in technical fields with very specific jargon. However, once I had my epiphany that this thing probably already exists somewhere, I was able to describe what I wanted to do to ChatGPT and it immediately informed me of the very nifty Cmd class.

Second, I’m not mad that I spent a month building a thing that already exists. Really. I learned so much going through the absurd process of building my own line-oriented command interpreter:

• Loops, baby, wow do I know some loops. Nested loops, infinite loops, breaking a loop, etc. For, while, you name it. Loops are my jam;
• If-else logic, my brain is mashed into a horrible, spidery decision tree. And by extension, boolean logic. Fucking hell, that was trial by fire. For example, I did not know None evaluates to False because in Python, it is “falsy.” I spent way too many hours trying to debug this, but now I will never forget it;
• I learned some Pytest and wrote a ton of unit tests for my command interpreter. I’m not going to say I’m good at writing unit tests yet, because I’m not, but I understand the concepts and the importance of unit testing, and I have a few tools to work with.
• I know what I want from a command interpreter. OK, I built a dumb one, but when I refactor my code to replace it with Cmd, I already know what features to look for and how I want to deploy it.

I’m going to put DonkeyFeed down for a bit now. I have to finish up some actual classes (SQL lol) for a degree I’m working on as the term comes to an end, and I have a couple other Python projects I want to pursue.

When I pick it up again, yeah, I’ll probably refactor the user interface to make it more robust and stable, with better error handling and help functions. And then I need to find a better way to package it (yikes) for distribution.

I guess the main thing I’m learning as I shelve this one for a bit is you never really finish a piece of software, you just kind of get it to a point where it’s not completely broken. Maybe you’ll have time to fix it more later!