Drop Symbol literals

[odersky]

In the spirit of dropping things, what do people think of dropping symbol literals? Saving one character between 'myName and "myName" in some rare cases seems not worth the syntactic complexity.

[Sciss]

I think that would be great; I never liked the syntax, especially as the ticks are also used for characters 'x', so it always looks like an unclosed character literal.

[densh]

If symbol literals are dropped, the whole scala.Symbol data type should probably be dropped as well. The only value of symbols is their marginally shorter syntax.

[dwijnand]

Perhaps they can be dropped when http://docs.scala-lang.org/sips/42.type.html lands?

[ritschwumm]

drop them, please. i never needed them in years, and was annoyed more than once by some editor's syntax highlighting becoming confused.

[odersky]

If symbol literals are dropped, the whole scala.Symbol data type should probably be dropped as well. The only value of symbols is their marginally shorter syntax.

Yes, but for the time being we'd need Symbol as a rewrite target. But it could be deprecated.

[SethTisue]

Yes please, let's drop this!

[milessabin]

I'd be happy to trade them for Byte and Short literals.

[sjrd]

We really need to start thinking about what we gain for all the code out there that we are going to break. To me it seems that in this case we gain only a bit of code in the parser, and I don't think this justifies all the breakage.

[Sciss]

Do we have a statistic about Symbol usage - because I bet that very very few people actually use it. And I thought the idea was anyway to have a rewriting tool. I think the gain is a significant simplification of the language, dropping a totally unnecessary feature; unless you embody symbols with some new power that distinguishes them from strings. To me it's like the proposal (on discourse) to introduce the let keyword - you end up with let versus val with no real gain except having to think twice what to use.

[milessabin]

shapeless's LabelledGeneric uses Symbol and an encoding of their singleton types, but with the benefit of hindsight that was a terrible mistake ... I should just have used String.

In the meantime, I think that first-class syntax should go hand in hand with first class singleton types, so we should have both (which is proposed in SIP-23) or neither (proposed in this issue). I think either of those options is preferable to the status quo.

[olafurpg]

Do we have a statistic about Symbol usage - because I bet that very very few people actually use it.

At the top of my head, Play Framework forms use symbol literals quite a bit, see examples in https://www.playframework.com/documentation/2.6.x/ScalaForms. Ammonite ops is another big user http://ammonite.io/#grep I can crunch numbers on my corpus, but I suspect symbol literals are more frequently used than you claim.

And I thought the idea was anyway to have a rewriting tool.

Play forms symbol literals are likely to appear in external DSLs files like Twirl templates that make automatic migration tricker. Same applies for ammonite scripts.

[odersky]

We really need to start thinking about what we gain for all the code out there that we are going to break. To me it seems that in this case we gain only a bit of code in the parser, and I don't think this justifies all the breakage.

It's actually much more than the parser, since symbol literals are constants, which makes them special in several respects. One aspect it SIP 23, as mentioned by @milessabin. I think it presents a certain awkwardness that all the essential infrastructure for strings has to be duplicated for symbols.

But I believe that's not the most significant cost either. That would be the necessity for us to keep teaching the concept and for programmers the risk of being puzzled when they see it.