Extracting parts from regular expression when pattern matching with `switch`

[johndeighan]

I was looking at the comments in another issue and found this suggestion:

switch a
  m := /(\d)/
    return m[1]

as a way of getting at groups within a matching regular expression.

I'm currently trying this, but it doesn't work:

switch a
  m^ /(\d)/
    return m

I thought that the result of the match would be assigned to the variable m
Your docs for pattern matching doesn't have examples of getting either the matched string or a subgroup from a regular expression.

Your docs need more (simple) examples of using regular expressions when pattern matching.
Meanwhile, is there any way to accomplish this using a switch statement?

[edemaine]

Alas, we do not currently have a way to get the matched groups from a regular expression in switch. On the other hand, you can do something like it with pattern matching if / declarations in conditions:

if [everything, part1] := a.match /(\d)/

For switch, we'd need to find a good notation. m^ is for assigning the thing that matched, in this case the entire string, not the matching result of the regular expression. I'm not sure what makes the most sense to name the pattern parts... but we're open to suggestions!