Course of Raku / Regexes and grammars / Regexes / Alternations / Longest token and first match
Quiz — Alternations
What does the following program print? Note the single bar
|.
say 'download' ~~ / down | download /;| 1 | ｢download｣ |
| 0 | ｢down｣ |
| 0 | ｢load｣ |
| 0 | False |
The single bar | uses longest-token matching: when more
than one alternative matches at the same spot, the longest one wins.
Even though down is written first and would match,
| prefers the longer download. With
|| instead, down would have won.