On 9 April 2018 at 03:41, Paul Lalonde <paul.a.lalo...@gmail.com> wrote: > A ^ normally matches either the start of string or the start of a new line > (with the m flag). > I'd like to match only starts of lines, but not starts of strings, ideally > without changing the regexp. > > My source data is in a ReadSeeker, and if I use > Regexp.FindReaderSubmatchIndex() I can get the first match - always the > start of string - and then Seek back to the end of that match to get the > next match. Sadly, that one also then matches start-of-string, and there's > no hope of finding my start of line locations. > > On a string or []rune I'd ask for FindAll and get a long list of my line > starts, but on a Reader it seems I'm hooped, as there is no All version. > > Any advice? My reader comes from a fairly complex data structure that can be > read in blocks - I was hoping to avoid managing expressions that might span > blocks by putting the data through a Reader interface. Is there a better > way?
I've encountered this issue before with other regexp packages and needed to adjust the API to make it possible. I don't think it's currently possible with the Go regexp package. Note that the internal "input" interface provides a "context" method which provides the required functionality (almost - the code currently assumes that position 0 is special). It would be possible, I think, to add another method to Regexp that allowed the caller to specify the EmptyOp context at the start of the of read data, although thinking of a good name for the method might be difficult. While we're on the subject, ISTM that FindReaderSubmatchIndex should really return []int64 not []int. A bit late now though. -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
