Tcl Source Code: View Ticket

Description:
In the following example, the resulting indices are wrong: `% regexp -indices -inline {(?:ab)+c} aaaabbbbcc {0 8}` The correct result should be: `% regexp -indices -inline {(?:ab)+c} aaaabbbbcc {7 8}`
User Comments:
sebres added on 2019-11-24 15:25:35: No. Although the sub-expression traverses over all `a` (and finally over all `b` without `a`), despite this not capturing it as a group - the whole expression matches all characters to first `c` inclusive it. So the result `{0 8}` is pretty correct - `{0..4}` `aaaab` within first iteration by `ab`, `{5..7}` `bbb` within second to 4th iteration by `(ab)+` and then finally `{8}` `c`. Note that `(?:ab)+` is neither a lookahead nor a lookbehind assertion (which is not implemented in tcl at all), so the whole match is captured for whole expression. How the iterations for first subexpression look, illustrating this example: % regexp -all -indices -inline {ab} aaaabbbbcc {0 4} {5 5} {6 6} {7 7}