Making a Python interpreter in 1024 bytes

aazhenley about 2 hours ago 28 commentsRead Article on austinhenley.com

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jrdres•31 minutes ago

The code makes me smile, because it's nasty. This isn't like C4, a tiny but complete C compiler which does error checking on its subset. Instead, this is worse than Sector C, which takes every shortcut and just plain assumes everything in the source is right.

This "Python" just plain assumes for keywords: Any "f" is a "for [x] in range[y]" (exactly that, no other for's). Any "w" is a "while". Any "i" is an "if". Any "d" is a "def". Any "p" is a "print("

Nasty, nasty.

(Also nasty is that the code snippets in the article has more comments than the github copy of the "readable" version. You need the article to understand what's going on.)

This is a just a bit too simple for a "Tiny Python". If somebody is willing to allow a few more K's of bytes, I'd love to see at least lists & dicts here--Lisp can do them!

teddyh•about 2 hours ago

For those who actually need something like this in production, there is Snek: <https://sneklang.org/> “Snek is a tiny embeddable language targeting processors with only a few kB of flash and ram.”

jrdres•about 1 hour ago

Yes, but compiling or modifying Snek from source is very challenging. I wish it was one single C file for an example base like Posix, instead of many files for many platforms plus a custom parser in Python (Lola).

anitil•about 1 hour ago

This is really cool! It's so fun to see what you can achieve and what's optional. I have seen the 'single character variable' limitation in some other minilangs before, but using the source itself as the target of function calls and loops is new to me. It does make a lot of sense but I wouldn't have thought of that.

tempodox•about 2 hours ago

This seems to be in the same spirit as Justine Tunney's SectorLISP. Very cool.

https://justine.lol/sectorlisp/

gabrielsroka•36 minutes ago

Or sectorC

https://github.com/xorvoid/sectorc

Edit: I wonder if sectorC could compile python1024

hankbond•about 2 hours ago

Good use of free will and well-written. Very nice walkthrough austin!

Scubabear68•about 2 hours ago

I was very disappointed that this is “interpreting” some tiny made up language.

This is not Python, or even within three orders of magnitude of Python.

stingraycharles•2 minutes ago

Yeah the amount of Python code that would work here is probably not a lot more than this specific FizzBuzz example. Lots of shortcuts taken, which I guess is understandable.

SPBS•about 1 hour ago

It’s true, the title should have said “Python-like”

benatkin•8 minutes ago

I like python subset. However, many don't see it that way.

happycube•about 1 hour ago

TBF the fizzbuzz code works just fine in CPython.

benatkin•6 minutes ago

Indeed, for some code, CPython and this interpreter produce identical output. I gave it an upboat.

TZubiri•about 2 hours ago

A lot of criticism of python often mentions the whitespace as lexical scope tokens, and that criticism is usually posited by users of the language.

As implementer of an interpreter, did you feel that whitespace for lexical scoping made the job of writing the lexer significantly more complex?

nomel•about 2 hours ago

And, there are multiple white space symbols!

is different than

So you also have to track the actual sequence of counts of white space used for each level, rather than just a simple count.

rmunn•about 2 hours ago

Or you just forbid mixing spaces and tabs in the same indentation sequence, the way most whitespace-sensitive languages seem to end up doing. Or you make a slightly more reasonable rule: spaces may follow tabs, but no tabs may follow a space. That's at least unambiguous.

fc417fc802•about 1 hour ago

But it also feels arbitrary and annoyingly restrictive. On top of that there are at least 25 whitespace codepoints in UTF. Should your language really be opinionated about when, where, and in what order (for example) the "mongolian vowel separator" appears?

jubilanti•about 2 hours ago

> <space><space><tab><space> is different than <space><tab><space><space>

in my view, both are the same, both `is` (or ===) an IndentationError raise

fc417fc802•about 1 hour ago

It's just a stack containing strings at the end of the day. Really not a big deal.

TZubiri•about 1 hour ago

Right, pointers to strings but yeah. Essentially the whitespace count specifies the stack depth at which a line is to be executed. A decrease in stack depth means all superior levels are terminated.

Doesn't affect function call stacks though.

TZubiri•about 1 hour ago

For a 1024 byte implementation (and even way more complex impl.) You would just force one whitespace char, and definitely no mixing.

zephen•about 1 hour ago

> that criticism is usually posited by users of the language.

Uhhh, no. Sure, it's posited by people who feel they are are forced to use it, but it's basically unlearning other syntax.

Here's a study about people with no experience. They do better with python:

https://www.researchgate.net/publication/262256894_An_Empiri...

When the scala language made whitespace optional, it was very divisive, but now it's extremely well accepted.

mbirth•27 minutes ago

At a former workplace where most stuff was done in PHP, some colleagues used whitespace very liberally. Like, indentation was just a random amount of whitespace, every line slightly different. Sometimes 2 or more spaces between keywords, etc.

After that experience Python code is like eye-bleach to me.

TZubiri•about 1 hour ago

I meant users of languages ( application programmers) as opposed to compiler programmers, not python programmers specifically, so I'm including devs that use other languages and see in python a tool that they would consume.

ni5arga•about 2 hours ago

the blog post is pretty well-written! loved how he wrote about the the code-golfing part.