3 ms·

In PHP, the "if ($a = 1)" and "if ($a == 1)" look a lot like each others. In the Python version, the new "(a := 1)" will stand out compare to the canonical "a

In PHP, the "if ($a = 1)" and "if ($a == 1)" look a lot like each others. In the Python version, the new "(a := 1)" will stand out compare to the canonical "a == 1" as the ':' and '()' are unexpected here, and scream that it's not regular if test.

dvlsg 8y ago
Same problem in Javascript. There's actually a yoda lint rule that encourages you to write your code like (1 === a) instead, so you don't accidentally make that mistake.
- makapuf 8y ago
  I hate Yoda assignment in C. Does no good when assigning to variables. I think it's better to use the weird (on purpose) ((x=13)) and forbid x=13
korijn 8y ago
I'm curious to see how it will pan out in practise, but I'm not getting my hopes up. I made a flake8 plugin to forbid assignment expressions: https://github.com/Korijn/flake8-assignexp https://github.com/Korijn/flake8-assignexp Will be released once python 3.8 is out and I can test it.
- geoelectric 8y ago
  That seems unnecessarily reactionary, but ok. I agree with the post you're responding to that having a completely separate token for inline assignment fixes the majority of issues that have historically come up with it (which mostly come down to forgetting an = in the ==). Might be worth feeling out the trajectory of the feature before proactively banning it from codebases you control.
  - korijn 8y ago
    You're right. Like I said, I'm curious to see how it will pan out, but I'm not getting my hopes up. I'm just not a fan of this new syntax. :) IMHO null-safe navigation operators like ?. and ?[] are much more important to have.
thomasahle 8y ago
The '()'s are not always needed though, as in the PEP examples `(y := f(x), x/y)` and `(x := 0, x := 1)`. The alternative `f(x) as y` syntax looked nice to my eyes, and doesn't introduce new symbols. However I'm sure they are right, that it would have bad corner cases.

dvlsg 8y ago

Same problem in Javascript. There's actually a yoda lint rule that encourages you to write your code like (1 === a) instead, so you don't accidentally make that mistake.

makapuf 8y ago
I hate Yoda assignment in C. Does no good when assigning to variables. I think it's better to use the weird (on purpose) ((x=13)) and forbid x=13

korijn 8y ago

I'm curious to see how it will pan out in practise, but I'm not getting my hopes up. I made a flake8 plugin to forbid assignment expressions: https://github.com/Korijn/flake8-assignexp https://github.com/Korijn/flake8-assignexp Will be released once python 3.8 is out and I can test it.

geoelectric 8y ago
That seems unnecessarily reactionary, but ok. I agree with the post you're responding to that having a completely separate token for inline assignment fixes the majority of issues that have historically come up with it (which mostly come down to forgetting an = in the ==). Might be worth feeling out the trajectory of the feature before proactively banning it from codebases you control.
- korijn 8y ago
  You're right. Like I said, I'm curious to see how it will pan out, but I'm not getting my hopes up. I'm just not a fan of this new syntax. :) IMHO null-safe navigation operators like ?. and ?[] are much more important to have.

thomasahle 8y ago

The '()'s are not always needed though, as in the PEP examples `(y := f(x), x/y)` and `(x := 0, x := 1)`. The alternative `f(x) as y` syntax looked nice to my eyes, and doesn't introduce new symbols. However I'm sure they are right, that it would have bad corner cases.