Why does `True == False is False` evaluate to False in Python? (2013)

Re:Why does `True == False is False` evaluate to False in Py... by jakear on Saturday May 02, 2020 @11:59AM (#23052495)

Huh that’s quite interesting. It behaves this way even when you explicitly make it an object literal rather than a block.

I guess JS’s parser explicitly prohibits adding things to a curly-brace enclosed entity?

I’m normally quite defensive of JS, but I’ll have to admit I don’t like that.

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Re:Why does `True == False is False` evaluate to False in Py... by Zarel on Sunday May 03, 2020 @04:16AM (#23057660)

How did you explicitly make it into an object literal?

    ({}) + []
    -> "[object Object]"

will correctly make it "[object Object]"

Did you try to do this?

    {a: 1} + []
    -> 0

That's interpreted as the statement 1 labeled a, not as an object. This makes it obvious it's not an object:

    {a: 1, b: 2} + []
    -> Uncaught SyntaxError: Unexpected token ':'

JavaScript supports labels so you can continue/break multiple levels at once:

    {
      a: while (true)
        while (true)
          break a;
    }

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Re:Why does `True == False is False` evaluate to False in Py... by jakear on Sunday May 03, 2020 @12:03PM (#23059823)

Yes, I realized after the fact that I was indeed making a label. I’m now back to not having an issue with JS

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Re:Why does `True == False is False` evaluate to False in Py... by esrauch on Saturday May 02, 2020 @05:26PM (#23055054)

It's just ASI (automatic semicolon insertion) and at the top-level {} declares a block not an object.

You can also do like ({} + []) and it will actually be "adding" them; the confusion solely comes from people typing into the JS console something that wouldn't make any sense to put into an actual script.

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