Feature #16370: Pattern matching with variable assignment (the priority of `in` operator)

• Status: Open
• Assignee: -
• Target version: -

[jnchito (Junichi Ito)]

I wrote this code:

n = 0
ret = n in 99
p ret

I expected ret was false but was 0 (truthy value).

I had to write like this:

n = 0
ret = (n in 99)
p ret #=> false

However, I would like to write ret = n in 99 because it is more natural for me, and I am afraid many people might mistake like me. Could you reconsider the priority of in operator?

[matz (Yukihiro Matsumoto)]

We have discussed about in-line pattern matching and made a decision that it should cause an exception instead of returning false. So this issue will disappear.

We might need to talk about the precedence for e.g. a = n in 99 rescue nil.

Matz.

[ktsj (Kazuki Tsujimoto)]

• Related to Feature #16355: Raise NoMatchingPatternError when `expr in pat` doesn't match added