Re: Repetition syntax

If I go look at https://invisiblexml.org/1.0/ixml.ixml.html and presuppose a US keyboard, we've got !, $, %, and \ currently not allocated as well as < and >. (Accepting that & and # are not available.)

I'd prefer to go with a variant on Liam's proposal of %{a,b} and %%{a,b} since @, like < and >, have deeply established meaning in XML context and it might be preferable to distribute the multiple uses more widely than ( and ).

But I don't find myself in the grip of strong opinions about this.

On Mon, Dec 1, 2025, at 11:13, Norm Tovey-Walsh wrote:
> Hello,
> 
> I think the idea of introducing repetition[1] into Invisible XML has been well received, there just remains the tricky and somewhat subjective question of what syntax to use.
> 
> In retrospect, it’s a real shame that we used up single “{“ and “}” for comments. But we did, that’s water under the bridge.
> 
> I propose <a,b> and <<a,b>> (parallel to * and **, and + and ++). I think it’s nice to delimit the beginning and the end, so a pair of brackets seems suitable. We can’t use (), [], or {} because those already mean something else. And we can’t use “#” as a delimiter because of hex escapes[2].
> 
> I think a single character could work: /a,b/ and //a,b//, for example, but it doesn’t strike me as obviously better.
> 
> Liam proposed @(a,b) (and, I assume, @@(a,b)). I think that could work too.
> 
> Any more suggestions?
> 
>                                         Be seeing you,
>                                           norm
> 
> [1] https://invisiblexml.org/pr/326/autodiff.html
> [2] I mean, technically, I think we probably *could*. I don’t think it would be ambiguous in the grammar, but I think it would be a mistake to make "a"#3 and "a",#3 both be legal and mean very different things. It feels like an invitation to error.
> 
> --
> Norm Tovey-Walsh
> Saxonica
> 
>