Making a Python interpreter in 1024 bytes
73 points by azhenley 3 hours ago | 25 comments

jrdres 22 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!

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teddyh 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.
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jrdres 47 minutes 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).
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anitil 52 minutes 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.
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tempodox 2 hours ago
This seems to be in the same spirit as Justine Tunney's SectorLISP. Very cool.

https://justine.lol/sectorlisp/

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gabrielsroka 27 minutes ago
Or sectorC

https://github.com/xorvoid/sectorc

Edit: I wonder if sectorC could compile python1024

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hankbond 2 hours ago
Good use of free will and well-written. Very nice walkthrough austin!
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TZubiri 3 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?

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nomel 2 hours ago
And, there are multiple white space symbols!

<space><space><tab><space>

is different than

<space><tab><space><space>

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

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rmunn 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.
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fc417fc802 2 hours 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?
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rmunn 28 minutes ago
I mean, obviously that one should only appear within Mongolian text and not within indentation.

To state explicitly what should be implicitly obvious, there is no valid reason (that I'm aware of, I welcome any non-facetious correction) to use any character except U+0009 and U+0020 within indentation. Horizontal Record Separator? Zero-width joiner? Language-specific whitespace characters like your example? All make sense within human text (well, maybe not HRS), but in programming, they should be eschewed in favor of the characters that can be typed in every single keyboard layout in the world. Even languages that don't put spaces between words, such as Thai, still put spaces between sentences (or comma phrases) and therefore keep the space bar in their keyboard layout.

And since mixing tabs and spaces (even between lines, where some lines are tab-indented and some are space-indented) creates problems for whitespace-sensitive langauge, there's a reason why every whitespace-sensitive language I'm aware of has tended to either outright forbid, or at least discourage, U+0009 and its ambiguous meaning (since its meaning isn't clear until you know people's editor configurations, which are usually not available to the validation code running in CI or on other people's machines).

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Mogzol 44 minutes ago
> and annoyingly restrictive

How so? In what scenario would you ever need to use a sequence like <tab><space><tab> in indentation in your source code? Let alone using esoteric Unicode whitespace characters for indentation. I think it is perfectly reasonable for the language to make the restriction that indentation must be either all tabs, tabs followed by spaces, or all spaces.

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fc417fc802 6 minutes ago
> In what scenario would you ever need to use a sequence like <tab><space><tab> in indentation in your source code?

Writing a lisp in an editor that doesn't do boneheaded things with tabs? That's the only one I've personally run into but lack of imagination is hardly a good excuse to implement arbitrary restrictions.

> Let alone using esoteric Unicode whitespace characters for indentation.

How do you know what's esoteric in other countries? I certainly don't. I'm not an expert in linguistics but I'm sure that people everywhere in the world write computer programs at this point.

> I think it is perfectly reasonable ...

Without any concrete justification? Why would entirely artificial restrictions ever be seen as reasonable?

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jubilanti 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

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fc417fc802 2 hours ago
It's just a stack containing strings at the end of the day. Really not a big deal.
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TZubiri 47 minutes 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.

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TZubiri 54 minutes ago
For a 1024 byte implementation (and even way more complex impl.) You would just force one whitespace char, and definitely no mixing.
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zephen 56 minutes 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.

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mbirth 18 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.

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TZubiri 51 minutes 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.
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Scubabear68 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.

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SPBS 2 hours ago
It’s true, the title should have said “Python-like”
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happycube 53 minutes ago
TBF the fizzbuzz code works just fine in CPython.
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ni5arga 2 hours ago
the blog post is pretty well-written! loved how he wrote about the the code-golfing part.
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