Repr value for nan

In Python:

>>> repr(float('nan'))
'nan'

while in RustPython:

>>>>> repr(float('nan'))
'NaN'

slight incompatibility but it is actually tested for in cmath.

(TIL NaN is lowercase in repr in python)

C also displays it as 'nan' if I'm not mistaken. I always remember seeing 'NaN' in Javascript tbh and Rust seems to follow that. Either way, 'NaN' always seemed weird to me, either capitalize em all or don't, why is a being left out like that? No respect for poor a.

Edit: Seems like the situation is trickier when Wikipedia has an entire subsection dedicated to how NAN is displayed.

@DimitrisJim

@DimitrisJim I would like to work on it
would you pls guide me a bit?

Yes! Take a look at float's repr function. This calls another function to handle formatting for the different values that might be passed in. Take a look there and try and find out which case Nan/Inf fall under and what you'd need to do.

RustPython/Lib/reprlib.py

s = builtins.repr(x)
# Bugs in x.__repr__() can cause arbitrary
# exceptions -- then make up something

repr(float('nan'))
returns the builtin repr function called with float('nan')

I am stuck here...

@Codemonk-adi

Hey @Codemonk-adi, not sure what you mean here. Are you looking inside the implementation of repr for PyFloat? You can always fire up a debugger and get through stepping your way until the end (it takes some getting used to but its worth it).

@DimitrisJim

@DimitrisJim I am sorrry to bother you again, but I am unable to use the debugger, when I run the debug option on vscode it opens an rust python interpreter, and I do enter debugging mode in vscode but the buttons are disabled.

@Codemonk-adi

@Codemonk-adi hop on over to gitter if you can. This way I can help you further w/o notifying watchers.

closed with #3103

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Repr value for nan #3034

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Repr value for nan #3034

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ShadowJonathan commented on Sep 10, 2021

DimitrisJim commented on Sep 10, 2021

Codemonk-adi commented on Sep 15, 2021

DimitrisJim commented on Sep 15, 2021

Codemonk-adi commented on Sep 16, 2021

DimitrisJim commented on Sep 16, 2021

Codemonk-adi commented on Sep 16, 2021

DimitrisJim commented on Sep 16, 2021

DimitrisJim commented on Sep 22, 2021

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