Is it possible to do boolean assertions with raku regex?

Question

In the apocalypses, there are some words about boolean assertions:

<( code )>            # call code as boolean assertion

However, I cannot make it work.

say "9471" ~~ m:g/ (\d) <($0 > 5)> /

I expect to only match numbers greater than 5, but I get a compile error.

Which is the correct syntax (if exists), or any alternative to do some boolean assertion?

Note that those are historical documents. The language changed a lot after they were written. — Brad Gilbert, Nov 21 '20 at 01:26

score 10 · Accepted Answer · answered Nov 19 '20 at 09:58

10

$ raku -e 'say "9471" ~~ m:g/ (\d) <?{ $0 > 5 }> /'
(｢9｣
 0 => ｢9｣ ｢7｣
 0 => ｢7｣)

answered Nov 19 '20 at 09:58

1

I'd say this is a documentation issue (can recall having the same quandary myself) ... perhaps raise as an issue to make the <{}> family more prominent...? – librasteve Nov 22 '20 at 18:27
@p6steve: By all means, please do! – Elizabeth Mattijsen Nov 22 '20 at 19:18
Ahhh - just being lazy - done now. https://github.com/Raku/doc/issues/3705 – librasteve Nov 22 '20 at 19:46

1 Answers1