Ok, then I've another suggestion. Let (:REGEX <string>) take optionally more symbols, and use place holders in <string> to insert corresponding syntax trees. For example:
[...]
Is that a better alternative ?
I don't think it's worth the trouble. My personal opinion is that for complicated regular expressions you should use the S-expression syntax anyway. YMMV, of course.
Ok. Indeed, it is adding too much complexity. I will stick with s-exp.
And thanks again for this great package !