Hi, does someone know all permitted characters in...

# announcements

[GarouDan]

Hi,

does someone know all permitted characters in backticks?

Until now we have the following:

val ` -!"#$%^&()*+,-=?@^_{|}~😡` = ""

Characters known to be not allowed:

.:/\[]<>

Is there a place that we can find this?

Related topics:
https://gist.github.com/Danilo-Araujo-Silva/36814f87cdf71177571e817aee040096
https://kotlinlang.org/docs/reference/java-interop.html#escaping-for-java-identifiers-that-are-keywords-in-kotlin
https://kotlinlang.org/docs/reference/coding-conventions.html#naming-rules
https://docs.oracle.com/javase/specs/jvms/se7/html/jvms-4.html#jvms-4.2.2
https://docs.oracle.com/javase/specs/jvms/se11/html/jvms-4.html#jvms-4.2

[Marc Knaup]

It's less if you also want to support Android:
https://source.android.com/devices/tech/dalvik/dex-format#simplename

[GarouDan]

Hum, interesting. I would like to use this in some enum of mine in my kotlin dsl code in buildSrc

[Marc Knaup]

I guess it's fine then since that's never run on Android 🙂

[Ubi]

@Test
    fun `angry path test 😡`() {
        TODO("not implemented") 
    }

wow we can even put some emojis.. not sure how useful that will be 😄

[GarouDan]

Huahuh, crazy, I think I’ll start using this ^^

[GarouDan]

I’ve updated the question ^^

[Ubi]

btw \ & / is not allowed either.

[Marc Knaup]

and . I guess

[GarouDan]

Yes, the aren’t allowed and I would like to use . and >. I was trying some against the ascii table and some of them are not allowed. It looks like if java uses it somehow the aren’t allowed, but I don’t know.

[Marc Knaup]

I think it's all characters which have specific meaning in JVM-internal names

[Marc Knaup]

like :;/.

[Marc Knaup]

no idea what \ is used for

[GarouDan]

I think maybe this is right, but I got the same conclusion of you, where we use \ in jvm? It’s kind of strange

[Marc Knaup]

And [ may also be forbidden

[Marc Knaup]

And < >

[Marc Knaup]

https://docs.oracle.com/javase/specs/jvms/se7/html/jvms-4.html#jvms-4.2.2

[GarouDan]

This does not explain everything but explains a part = )

[Marc Knaup]

It doesn't explain \ and >

[Marc Knaup]

the latter is probably reserved because of <init> and <clinit>

[Marc Knaup]

like <

[Czar]

\ is the escape character, > is math op and right part of arrow.

[Marc Knaup]

But not in a JVM internal symbol name

[Czar]

Here are the rules, I'm not sure if reason for everything is explained there, but some for some things it is:
https://docs.oracle.com/javase/specs/jvms/se11/html/jvms-4.html#jvms-4.2

[Marc Knaup]

Yeah that's that I've posted.
I read over > being disallowed.
It doesn't explain \ though, which is only disallowed in module & package names.

[Czar]

Heh, missed it somehow 😉 Sorry

[Czar]

Oh, actually, no, not sorry 🙂 Mine is better 😛
Take a look, there are explanations there

[Marc Knaup]

It's almost the same link 😛 😛

[GarouDan]

Huhu, it looks like the se11 give us more clues

[Czar]

Yup, almost, with only just 8 years of development difference between them 🙂

[Marc Knaup]

oh it's 11, read over that too 😄

[Marc Knaup]

shouldn't code at the same time 🙂

[GarouDan]

So, can we say, everything that is different from not allowed by the naming rules are allowed? ^^

[Marc Knaup]

¯\_(ツ)_/¯

[GarouDan]

val `¯_(ツ)_¯` = ""

[Czar]

I'd say yes, unless Kotlin compiler complains for its own Kotliny reasons 🙂
I would also be careful with using this in production code, it tends to bite the user in the (‿ˠ‿) at most unexpected moments.

[GarouDan]

Hehe, it’s true. But since I can take a lot of benefit from a name convention of mine I think I’ll put it agains some tests, but I’ll be using some not too weird ones.

Either way, I’ve created this gist: https://gist.github.com/Danilo-Araujo-Silva/36814f87cdf71177571e817aee040096

For future references.