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Maximum number of arguments in Python

See original GitHub issue

Hey! Quoting your documentation,

When I say it supports everything I really mean everything:

I hate to be that guy, but I’m using your library (which is really amazing, by the way) and I actually encountered this issue in a poorly designed JS file. Reproduction:

test_str = "arr = new Array({})".format(','.join([str(x) for x in range(257)]))
import js2py
ctx = js2py.EvalJs()
ctx.execute(test_str)

💥

Traceback (most recent call last):
  File "/home/liam/.virtualenvs/scraper/lib/python3.5/site-packages/js2py/evaljs.py", line 171, in execute
    compiled = cache[hashkey]
KeyError: b'bT(\xc0iho\x10\xc1q\xe6\x8c\xd1 \xe8U'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/liam/.virtualenvs/scraper/lib/python3.5/site-packages/js2py/evaljs.py", line 174, in execute
    compiled = cache[hashkey] = compile(code, '<EvalJS snippet>', 'exec')
  File "<EvalJS snippet>", line 3
SyntaxError: more than 255 arguments

I guess not much you can do, right? Maybe document it?

Issue Analytics

State:
Created 7 years ago
Comments:19 (13 by maintainers)

Top GitHub Comments

1reaction

PiotrDabkowskicommented, Nov 18, 2016

There is no point solving this specific issue, there are much more edge cases which are almost impossible to solve with the current approach - eg recursion limit of python. I will solve all the problems by implementing a proper interpreter.

0reactions

hut8commented, Nov 17, 2016

Hey @PiotrDabkowski looks like this thread got pretty off-topic. My use case is actually for Arrays only. I think that one AST transformation here would suffice. Specifically, if you could change:

Array( ... ) ➡️ [ ... ]

that would solve my real-life problem 😄 I’m not a JS guru like yourself, but I believe array literals and the Array constructor are exactly equivalent. I’ve done this in the interim for the project I’m working on but I used a horrible regex hack that I’m pretty ashamed of.

For the actual code that I was testing to crash this, it was at: http://www.startimes.com/f.aspx?t=36588040 (check out var topics = Array(...). The code is so poorly architected that this simple web scraping project I’m working on turned into what felt like cryptanalysis 😉

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