> Wish I had a Q[;;;] expression inside a regex You can put any Raku code that produces a string into a regex by using the syntax `$(code)`.
So this displays `True`: ``` say so Q[ <foo></foo> / ;;; ^&%%$$ ] ~~ / $( Q[ <foo></foo> / ;;; ^&%%$$ ] ) / ``` as does: ``` my $string = Q[ <foo></foo> / ;;; ^&%%$$ ]; say so $string ~~ / $( $string ) /; ``` ---- > when does regex NOT start reading at the > beginning of the input data stream? Never. It *always* starts at the beginning of the input. > Why does it need the ^ You use `^` when you want a pattern to be *anchored* to the start, so that if it fails at the start then that's it. To understand this, consider an example. Let's say you have an input string 'foo'. An `/ oo /` regex will match, because it doesn't contain an anchor, so the pattern is free to match *anywhere* in the input string. That is, while it *fails* to match *at the start*, because an 'o' does *not* match an 'f', *it keeps going*, and then succeeds when *the next* two input characters *do* match. In contrast, `/ ^oo /` will *not* match, because the `^` "anchors" the match to the *start* of the input string, i.e. immediately before the 'f' in 'foo', and the first 'o' in `^oo` does *not* match the 'f', and given that the match is *anchored* to the start, if it fails at the start, it gives up. ---- I've no idea what was causing your hang, but fwiw it doesn't make sense to me that it happened due to a zero length input or an undefined variable. ---- love, raiph
