It is nice. I'll have to play with this as well. Thanks again everyone.
On Friday, February 2, 2018 at 5:49:15 PM UTC-6, johnbclements wrote:
> > On Feb 2, 2018, at 3:21 PM, Matthew Butterick <m...@mbtype.com
> >> On Feb 2, 2018, at 10:23 AM, 'John Clements' via Racket Users <
> >> This macro gets the names in much closer to the corresponding patterns
> than matching by index, but it doesn’t actually embed the names into the
> > If you like keeping the names and patterns together, you could also
> create an association list of the names and subpatterns, and iterate:
> > #lang racket
> > (define msg "2018-02-02T11:26:34 someuser some-computername01
> 22.214.171.124 something broke")
> > (with-input-from-string msg
> > (thunk
> > (for/hash ([(name pat) (in-dict '((date . "[-\\dT:]+")
> > (username . "\\w+")
> > (hostname . "[-\\w\\d]+")
> > (ip . "[\\d\\.]+")
> > (message . ".+")))])
> > (values name (car (regexp-match (pregexp pat)
> Oh, that’s nice.
> In fact, I’ll tell you what I *really* like about that; it could radically
> simplify the irritating process of debugging regexps by breaking them in
> various places to perform a binary search; you could instead provide a nice
> error message specifying exactly which part of the regexp failed to match.
> One thing to be aware of is that you’d need to make sure that your regexp
> still works without backtracking. If you broke #px”.*abc” into #px”.*” and
> #px”abc”, it wouldn’t mean the same thing any more.
> > '#hash((message . #" something broke")
> > (date . #"2018-02-02T11:26:34")
> > (username . #"someuser")
> > (hostname . #"some-computername01")
> > (ip . #"126.96.36.199"))
> > --
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