Nested Named Patterns/Groups

[7fe]

So there is a proposal currently to get named pattern groups in RegExp. I'm only really familiar with pattern matching in Mathematica so I can't comment on other languages but it would be nice if the proposal supported something like named grouped pattern matching from the get go. Matematica uses : which is kinda taken for obvious reasons. name : pattern.

Basically they are nested. all references the entire array and first references 1. Here is an example using Isiah's syntax.

match ([1,2,3]) {
  all of [first of 1,2,3]: ...
}

[bterlson]

This can be accomplished in a few ways:

match (str) {
  // with my proposal in #11
  someRe -> { matches: { name } }: 1

  // with an as/is/of proposal
  is someRe of { matches: { name } }: 1

  // with static support for RegExps which might be neat...
  /(?<year>\d{4})-(?<month>\d{2})-(?<day>\d{2})/u: year + month + day
}

[rattrayalex]

Static support for RegExps discourages moving them to constants, which is sometimes better code (eg; where the same non-trivial regexp is being used more than once).

Another concern to keep in mind is that if some kind of or support is added, this can get tricky (eg; is someRe or someStr of { matches }: matches.length).

🚲 🏚 – into or with might be nice keywords for this.

[7fe]

I illustrated with an example which I believe would be valid syntax using Isiah's syntax.

case([1,2,3]) {
  all of [first of 1,2,3] => 
}

@isiahmeadows is this acceptable Isiah?

[dead-claudia]

@limeblack Close:

case([1,2,3]) {
  all = [first = 1, 2, 3] => ...,
}

• all is [1, 2, 3]
• first is 1

---

Please do familiarize yourself with my proposal, tracked by #17 here. It has a lot of functionality in its syntax.

[zkat]

Hey y'all! #65 has gotten merged, and a lot of issues have become irrelevant or significantly changed in context. Because of the magnitude of changes and subtle differences in things that seem similar, we've decided to just nuke all existing issues so we can start fresh. Thank you so much for the contributions and discussions and feel free to create new issues if something seems to still be relevant, and link to the original, related issue so we can have a paper trail (but have the benefit of that clean slate anyway).

The new spec -does- talk about everything in this specific issue, though, so I think this can be considered resolved. There's even specific examples using RegExp.