Replacing `import` with `accio`: A Dive into Bootstrapping and Python's Grammar | Hacker News Reader

Replacing `import` with `accio`: A Dive into Bootstrapping and Python's Grammar

mathamy.com

153 pointsThePhysicist28 comments

Summary of Blog Post (I'm not the author):

At Hacker School, I've been building an alternate universe Python by overwriting builtin functions and statements with Harry Potter spells. This is a thing you can do at Hacker School!

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This kind of stuff is why I read Hacker News. Completely pointless but indisputably awesome technical hacks that teach you something about how stuff works anyway.

Awesome, but accio is a bit Potterish. How about 'have' or something shorter.

Feel free to make your own project which is based on the theme of using words like 'have'.

You know its deliberately potter-ish, right? Did you miss the wingardium leviosa reference at the beginning of the post?

And avra kadabra to you also.

Huh, now I'm wondering how much you'd have to do to make the import keyword a build-time command-line argument

I am wondering how to add keywords at runtime, or remove all the keywords and make them functions...

I was expecting the magic to be changing

    import math
    x = math.ceil(y)

into

    x = accio ceil(y)

and having it Just Magically Work (tm).

But it's a nice write up of recompiling Python with a changed grammar.

I don't know how you could possibly have expected that.

Hence the "magically" :-)

I'm not a python programmer. But shouldn't this be possible at runtime by modifying the AST to change it back to import in the AST? That way you could have a module you can just include to run this without a custom interpreter.

Edit: Looks like this is doable by messing with the tokenizer: http://stackoverflow.com/questions/214881/can-you-add-new-st...

You could create a loader.py where you tokenize the script yourself, and replace accio with a custom import that again loadds imports by tokenizing them yourself first. And then after you've modified the tokens you should be able to build a valid AST and run it :)

I'm pretty sure you can just throw a SyntaxError there yourself too if you encounter a real "import".

Nice hack nevertheless.

I think you wouldn't be able to generate a valid AST to begin with since the parser would probably complain that it doesn't know the "accio" keyword, but I'm note 100 % sure if there isn't a workaround for this.

Yes and no.

The regular python parser will barf on that unknown keyword, so you don't get an ast because the parser never gets there.

Using import hooks, this can be done in a regular interpreter. For example, that's how hy, a lisp in python, works!

Oh yes, you can. But once you're doing that, why stop at a single statement? Why not macros https://github.com/lihaoyi/macropy

Don't forget http://www.pocoo.org/projects/karnickel/#karnickel the magnificent

its probably easier to add custom syntax to python by using custom encodings. The dropbox pyxl library does this. Details: https://github.com/dropbox/pyxl#implementation-details

When I search for "Harry Potter Programming Language" I keep getting references to an article where JK Rowling's writing process is used as an analogy for the creation of Python.

Is there an interesting story behind that search? You got me wondering.

this is such a great assignment for a principles of programming languages class. there is no better way to learn something than to break it up, change it and make it do your wish. i'm going to be teaching my next batch of muggles this.

Reminds me in some ways of LUA: https://github.com/mniip/LUA

Awesome hack!

Did you consider import hooks to accomplish this? Of course that wouldn't make your bootstrap language any different; that'd still be vanilla python. In the imported file you can do whatever you want, for example the inimitable paultag implemented hy, a python lisp, using those.

Wow. Such an awesome article. I really enjoyed reading it.

Really neat post, but a missed opportunity in naming it: "Basilisk" would have been quite a nice fit with both worlds ;)

Did you see she named it Nagini? Arguably even better

If you just want to accio act as import, you can always do this:

    accio = __import__

Anyway, interesting article!

Read the article, that was discussed and dismissed. It doesn't make accio 'act as import' because import is a keyword not a function call.

import is a statement. __import__ is a function hence will work.

    In [1]: accio = __import__
    
    In [2]: accio("os")
    Out[2]: <module 'os' from '/usr/lib/python2.7/os.pyc'>

From the article...

    >>> accio = __builtins__.__import__
    >>> accio sys
      File "<stdin>", line 1
        accio sys
                ^
    SyntaxError: invalid syntax
    
    # :(

The author wanted accio to replace import not __import__.

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