Gleam: Support literal values in guards

[lpil]

case x {
  _ if x == 1 -> "here we are using an Int literal"
}

• [x] Int
• [x] Float
• [x] Tuple
• [x] List
• [x] Records
• [x] String

If you pick up this ticket please no more than one implementation per PR please so that it is easier to review. Thanks!

[kyle-sammons]

Working on this!

[lpil]

Thank you @kyle-sammons ! Let me know if you would like any pointer on implementation

[gamebox]

Just a suggestion but what about.

case x {
  1 -> "this is an int literal pattern"
  _ -> ""
}

[lpil]

That would be a better way to express that, it's more an example to explain the syntax.

A slightly more realistic example might be something like this:

case x {
  Ok(i) if i > 3 -> True
  _ -> False
}

[gamebox]

Could you add some detail about what this looks like for compound types?

[lpil]

Does this help?

case x {
  Ok(i) if i == [] || i == [1] -> True
  _ -> False
}

[lpil]

Hi @kyle-sammons are you still working on this? Thanks

[QuinnWilton]

I'm interested in taking a stab at the tuple implementation if no one is currently looking at that :)

[kyle-sammons]

@lpil I am, I am. Hopefully finishing up the tuple implementation today. @QuinnWilton you can totally take either the List or Record one if you want to help out!

[QuinnWilton]

Thanks @kyle-sammons! I'll likely start work on one of those tasks in the next few days if you haven't gotten to them by then :)

[QuinnWilton]

Just an update -- I have not started work on the list implementation. I've been spending my time thinking about another issue (#34), so list and record support are both unclaimed at the moment.

[tomwhatmore]

No-one's working on those last two right? I'll do lists now and unless there's any other takers I'm happy to do records too.

[kyle-sammons]

@tomwhatmore Hey-o, I've actually been working on the list implementation. If you want to knock out the record one, though, go for it! :)

[tomwhatmore]

@kyle-sammons Sure, no problem, I'll do records instead.

[tomwhatmore]

Is there a reason why string literals aren't on this list?

[lpil]

I forgot! Oops!

On Fri, 22 May 2020 at 11:14, Tom Whatmore [e-mail] wrote:

Is there a reason why string literals aren't on this list?

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[tomwhatmore]

That is a good reason. I'll add them in a new PR.

[lpil]

@kyle-sammons Are you working on this? :)

[kyle-sammons]

@lpil So sorry, but I don't think I'll be able to finish off the list implementation. Life has gotten increasingly complex with the recent pandemic and taken away most of my free time 😞

[lpil]

No problem at all, I totally understand! Thank you for the work so far 💜