hmm, the perldelta doesn't talk about quantifiers, and the ambiguity would already have existed before.

I thought it's deprecated to facilitate parsing extended syntax like /abc(?{print "Hi Mom!";})def/

see perlretut for other examples

so I'm not sure if it's about quantifiers...

Because (? is invalid syntax on its own, in any (?X pattern the X is unambiguously special or incorrect, but never litteral. perlre however does talk about extending the quantifier syntax.

like making the lower bound of a quantifier optional

And any new syntax that's not a modifier can be added with a (?X pattern. That's why I concluded that disallowing unescaped litteral { was probably an opening toward new quantifier syntax (because { only introduces quantifiers). I thought of something like /.{{!($_ % 3)}}/ instead of /(?:.{3})*/ (it's harder to read though ...), or even "3ABCD" =~ /(\d)(.{{$1}})(.*)/; #(3,"ABC", "D"). But that's wild guesswork

PS: How do you like all those unbalanced left tokens? ^^"

Thanks, in hindsight all these explanations and reasonings make sense.

I just expect documentation to be clearer.

Cheers Rolf
_{(addicted to the Perl Programming Language and ☆☆☆☆ :)
Je suis Charlie!}